#help-49

1 messages · Page 145 of 1

latent elk
#

No

#

A force doesnt need to be 0 at t=0

#

It could be any number

jolly roost
#

but then how would it be at rest

latent elk
#

Cause before t =0, there's no force being applied

#

So its at rest

#

Then at t =0, we apply a force

#

So its no longer at rest

#

I think u messing up F and V

#

Function of V need to be continuous, Function of F doesnt

jolly roost
latent elk
#

So t = 0, F= 0?

jolly roost
#

yea

latent elk
#

Then solve like this

#

Since we know t = 0 => F =0 and t = 4 => F = 4, and F changes linearly

jolly roost
latent elk
#

This the graph must be a triangle

latent elk
#

The initial problem clearly state that the force is steady, AKA F = const

#

And not at t = 0, F = 0

#

Thats a wrong assumption

#

At t = 0, F = 4 because, we know at t = 4, F = 4, and F is const!

jolly roost
#

ok imma change up the question

A smart cart is initially at rest and then is influenced by a increasing linear force. The cart has a mass of 1 kg. At 0 seconds, the force is at 0 N. At 4 seconds, the velocity of the cart is 4 m/s. What is the impulse?

#

now?

latent elk
#

Using your graph

jolly roost
#

but why cant we just use I = mv

#

and do 1(4)

latent elk
#

Sorry

#

a

#

not v

jolly roost
#

hmm i see

#

so if acceleration is not constant, then we can't use I = mv?

latent elk
#

F is variable thus a is also changing according to F

jolly roost
#

and vi is 0, so deltaV = vf

latent elk
#

Well

#

Its just then u need to calculate dv over that 4s

#

which is not straight forward

#

At t = 0

#

F =0

#

F = ma

#

f = m * dv/dt

#

We might need to use jerk

#

Since its dF = m * da/dt

#

dF = m * d(dv/dt)/dt

jolly roost
#

but is the answer still 2Ns?

latent elk
#

Using F-t graph now is more fissable then doing integral at this point

jolly roost
#

but i still dont get why we cant simply use m(vf - vi) = 1(4 -0) = 4

#

is it because there is a change in acceleration?

latent elk
#

If F is linear

#

Then a is linear

#

But v will be not a linear

#

So over large time period (4s) we cant use v(at 4) - v(at 0)

jolly roost
#

i see

#

so what would vi be in that case then

midnight plankBOT
#

@jolly roost Has your question been resolved?

midnight plankBOT
#
Channel closed

Closed due to timeout

Use .reopen if this was a mistake.

#
Available help channel!

Send your question here to claim the channel.

Remember:
Ask your math question in a clear, concise manner.
Show your work, and if possible, explain where you are stuck.
After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!

Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.

native ruin
#

How do you figure out this problem? I just need help on what to find to get the answer.

I am thinking that I need to find M, then find that section of K, which then I add 8 to. Would that be correct?

fallow scarab
fickle harness
#

thts the trick

#

k=12

vale zephyr
fickle harness
#

use 20/15=x/8

#

sorry 10.667

#

can counter check

#

this question is solved

midnight plankBOT
#

@native ruin Has your question been resolved?

midnight plankBOT
#
Channel closed

Closed due to timeout

Use .reopen if this was a mistake.

midnight plankBOT
#
Available help channel!

Send your question here to claim the channel.

Remember:
Ask your math question in a clear, concise manner.
Show your work, and if possible, explain where you are stuck.
After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!

Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.

terse gulch
#

So with logarithms, we have (b^e = N ) = (log b of N = e) ... I know that logs with negative bases are undefined, but then why can we easily see that log (-4) of (-64) = 3 ? It's not undefined if I can calculate it, no ? Or am I missing something ?

terse gulch
#

Initial problem was this :

runic hamlet
#

you dont usually want to only evaluate very specific inputs

#

you are often much more interested in all of the inputs

#

and for negative basis and negative inputs you get huge problems

surreal moon
#

(in real numbers)

runic hamlet
#

yes you can define individual exceptions but those are very much exceptions

surreal moon
#

btw you can have negative logs if you deal with complex numbers. But the exact workings are pretty .. uhh... complex. catglasses

terse gulch
#

so we just apply the blanket rule that log with negative bases are undefined because of the times it's impossible to calculate them, like for log-4 of -16 or any other of the same type ?

burnt flame
#

well logs of negatives work in specific cases, but again, they're specific

surreal moon
#

We leave negative logs as undefined because, for any $n<0$, $n^x$ will not be real for most $x$

terse gulch
#

yeah, I'm currently only working with real numbers, I think this is precalc for now

grand pondBOT
burnt flame
#

like (-2)^2 is real but (-2)^(1/2) isnt

terse gulch
#

ah gotcha, so really it's to avoid the complexity in real number systems... this feels like something the teacher is going to go "remember when I said that?... well it's not 100% true"

#

but thanks, that makes it somewhat better because I know the rule, I was wondering why we applied even for "solvable" cases. but what SWR said sounds good to me

#

.close

midnight plankBOT
#
Channel closed

Closed by @terse gulch

Use .reopen if this was a mistake.

midnight plankBOT
#
Available help channel!

Send your question here to claim the channel.

Remember:
Ask your math question in a clear, concise manner.
Show your work, and if possible, explain where you are stuck.
After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!

Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.

pseudo karma
#

Convinced my book is wrong, ive come up with 439 every which way.

grim vector
#

You have to evaluate ?

dawn dagger
pseudo karma
#

Book giving answer as 443

#

I have no idea how to insert this on a phone calculator I havent done math in 20 years.

dawn dagger
#

,calc 2 + 21^2

grand pondBOT
#

Result:

443
grim vector
#

2+5 = 7

#

7*3

#

21

#

21²

#

441

pseudo karma
#

How is 6-8 = 2

dawn dagger
#

abs value

grim vector
#

Abs

keen herald
#

Absolute value of 6-8

dawn dagger
#

train abs

pseudo karma
#

Omfg lmao

#

No wonder, thank you.

grim vector
#

Nw

pseudo karma
#

Yeah thats right strait bars down are Absv

#

Thank again.

#

.close

midnight plankBOT
#
Channel closed

Closed by @pseudo karma

Use .reopen if this was a mistake.

#
Available help channel!

Send your question here to claim the channel.

Remember:
Ask your math question in a clear, concise manner.
Show your work, and if possible, explain where you are stuck.
After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!

Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.

calm fiber
#

How would i approach this problem?

midnight plankBOT
#

@calm fiber Has your question been resolved?

calm fiber
#

<@&286206848099549185>

fervent ember
#

use the given informations. "the diagonals of any rhombus are perpendicular bisectors of ech other" - what does this mean to you?

midnight plankBOT
#

@calm fiber Has your question been resolved?

calm fiber
fervent ember
#

no.

calm fiber
#

why not?

#

each triangle has the two sides

#

and using pythagorean theorem each side should be the same

fervent ember
#

what does it mean for the diagonals?

calm fiber
#

they are at right angles? they have been cut into two equal halves?

fervent ember
#

yes. use this information.

calm fiber
#

would i first try to find the mid point in this case?

#

or the center

#

and then the distance from A or C to the center

fervent ember
#

you have A and C given, so it is clear to determine the point of intersection of the two diagonals.

calm fiber
#

yeah ik that i can do

#

but my main issue is where to go from there

#

i can also find the equation of the perpendicular line which consitutues of b and d

fervent ember
calm fiber
#

hmm ok

#

but the thing im genuinely stuck on how to proceed 😭

fervent ember
#

did you determine the point of intersection?

calm fiber
#

yes

#

(3,2)

fervent ember
#

and now determine a perpendicular vector.

calm fiber
#

the equation of the perpendicular line?

#

is that what you mean?

#

yeah i did that too

fervent ember
#

so whats the remaining question?

calm fiber
#

a) Determine possible coordinates for B and D 😭

fervent ember
#

any point on this line?

calm fiber
#

would i say any points in (said line)?

#

oh

#

oh my gosh

#

bruhhhhhhhhhh

#

thank you thank you

#

so turns out i basically solved this question

#

but i thought it had to be specific

#

😭

#

this is genuinely frustrating

midnight plankBOT
#
Channel closed

Closed by @calm fiber

Use .reopen if this was a mistake.

#
Available help channel!

Send your question here to claim the channel.

Remember:
Ask your math question in a clear, concise manner.
Show your work, and if possible, explain where you are stuck.
After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!

Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.

maiden forge
#

open

midnight plankBOT
maiden forge
#

im doing this problem

#

ive done this bit so far

#

im stuck on the top right corner

#

im trying to simplify the root 6

#

and got root 3 x root 2

#

i dont know if ur supposed to get two of those prime numbers

silent elbow
#

you already have a root 3 in the denominator and the you can get a root 2 from the 14

maiden forge
#

14 is like a normal number its not in the surd bracket thing

silent elbow
#

I've never heard of a surd in math before. What are you refering to?

maiden forge
#

u dont know surds??

#

oh wait

#

u might call it something else to be fair

silent elbow
#

I probably do, but maybe they're called something different were you are from

tired vapor
maiden forge
#

yeah

maiden forge
dawn dagger
maiden forge
#

@versed summit

tired vapor
maiden forge
#

nvm

#

im gonna ping helpers

silent elbow
#

I'm working on it, just slow in latex

versed summit
tired vapor
#

essentially with your question, just simplify the square roots by factorizing. for example $\sqrt{28}=\sqrt{7\cdot 4}=2\sqrt{7}$

grand pondBOT
versed summit
maiden forge
#

did this so far

#

i think i simplified the top part correctly

tired vapor
#

try getting both in terms of $\sqrt{3}$, so you can make it one term (your top part is correct)

grand pondBOT
versed summit
#

Very good

silent elbow
#

$14\sqrt{6} \cdot 5\sqrt{3} = 7 \sqrt{2} \sqrt{2} \sqrt{3} \sqrt{2} \cdot 5 \sqrt{3} = 7\sqrt{2} \cdot 2 \cdot 3 \cdot 5$

versed summit
#

Alright what do you notice now?

silent elbow
#

That's for the denominator

versed summit
#

Maybe something in the numerator wink wink?

maiden forge
#

that looks so cofnusing

silent elbow
#

Yeah agreed

maiden forge
#

ive tried simplifying this part of the numerator

#

but i got two prime numbers and dont know what to do now

grand pondBOT
#

Gruttan

versed summit
maiden forge
#

oh yeah i did that bit

silent elbow
#

Maybe that's sligtly better

versed summit
maiden forge
versed summit
#

You can simplify it further?

maiden forge
#

heres what i did so far for the numerator but i know you can do 30 x 10 x 7

#

so 2100 on numerator

versed summit
maiden forge
#

ok

maiden forge
#

it just looks confusing in text format if you get what i mean

versed summit
#

Now you got 5root3 multiplied by 14 times root3 times root2

#

What do you see?

silent elbow
versed summit
#

Also Idk latex yet, pls help me @silent elbow

maiden forge
versed summit
maiden forge
versed summit
maiden forge
#

oh yeah nevermind

#

yeah sorry about that

versed summit
versed summit
#

You should continue from here

maiden forge
versed summit
#

What law do you think we're breaking?

maiden forge
#

i didnt know u could have two primes when from when you simplify it

versed summit
versed summit
#

Because this is just that but with the square root sign on top

maiden forge
#

as in i didnt know u could simplify it and leave it as this

#

because isnt it basically root 6

silent elbow
versed summit
versed summit
maiden forge
versed summit
maiden forge
#

so the root 3 x root 3 gives us 3 on its own

versed summit
#

Yes

maiden forge
#

so we do like 5 multiplied by 3 to get 2100/14 root 2 x 15

#

?

versed summit
#

We can do 14*5=70

#

70*3=210

#

That's better because we can directly cancel the 2100

maiden forge
versed summit
#

There would be a root 2 in the denominator though

maiden forge
versed summit
maiden forge
versed summit
maiden forge
#

ah ok

versed summit
#

If you think like this you can start solving these in your head and become a pro

#

Now all you got to do is get the final solution

maiden forge
#

finding out answer now

#

5 root 2?

versed summit
maiden forge
#

oh ok cool

#

thank you so much

versed summit
silent elbow
#

ggs guys😎

versed summit
maiden forge
#

yeah ur explanation actually helped out a lot

#

i got a different type now

versed summit
maiden forge
#

adding them

versed summit
#

Ok what do you think?

maiden forge
#

this looks easier than the previous ones

#

you just add the normal numbers outside the surd?

silent elbow
#

I would suggest trying it on your own for a minute or two, and then if you get stuck ask for helpcatthumbsup

versed summit
#

Yes

maiden forge
#

so in this case 7 root 3?

versed summit
#

5+3=8

#

So 8root3

#

Alright if that's it, I gotta go now, I have to sleep

#

Gn y'all

maiden forge
maiden forge
versed summit
silent elbow
midnight plankBOT
#
Channel closed

Closed by @maiden forge

Use .reopen if this was a mistake.

midnight plankBOT
#
Available help channel!

Send your question here to claim the channel.

Remember:
Ask your math question in a clear, concise manner.
Show your work, and if possible, explain where you are stuck.
After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!

Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.

stark harbor
#

i need help

midnight plankBOT
stark harbor
#

im not sure how to do scenario 1 question 6

#

and scenario idk how to do scenario 2 ques 4,5

#

.close

midnight plankBOT
#
Channel closed

Closed by @stark harbor

Use .reopen if this was a mistake.

stark harbor
#

.reopen

midnight plankBOT
#

wet pollen
stark harbor
#

hi

midnight plankBOT
#

@stark harbor Has your question been resolved?

midnight plankBOT
#
Channel closed

Closed due to timeout

Use .reopen if this was a mistake.

midnight plankBOT
#
Available help channel!

Send your question here to claim the channel.

Remember:
Ask your math question in a clear, concise manner.
Show your work, and if possible, explain where you are stuck.
After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!

Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.

fresh abyss
#

Why wouldn't choose 1 be optimal solution? You will always be part of the winning pair and receive payouts?

rose trout
#

No. If the chosen numbers are 0.1, 0.7, 0.8, 1 for instance, the middle pair wins.

fresh abyss
midnight plankBOT
#

@fresh abyss Has your question been resolved?

fresh abyss
#

<@&286206848099549185>

midnight plankBOT
#

@fresh abyss Has your question been resolved?

fresh abyss
#

@gray widget Please anyone?

#

I just need a small hint

fresh abyss
eager galleon
#

you have to set up some integrals and find the expected value of (X+A) - (B+C) with A,B,C being uniform random variables in [0,1] and X being the number you pick and then maximize its value

#

unfortunately i don't have the brainpower right now to explain better but i hope it works as a hint

fresh abyss
#

Bc I’m unsure how to take into considerations the value of X relative to the three others (since that affects which pairing is made)

eager galleon
#

i'd presume yes, assuming A is the partner number, case 1 being A >= B, C (or B,C >=A) and case 2 being B >= A >= C (can replace B and C)

#

i think you have to multiply by some constant somewhere because of the different possible orderings of A,B,C

#

take it with a grain of salt, i still haven't worked out a solution

fresh abyss
#

The thing I don’t logically understand with this problem is how there can be an optimal answer. Isn’t the best value of X entirely dependent on what 3 numbers were drawn? Since it’s uniformly distributed, each number is equally likely, so if there is a high variance among the other numbers, you want to go for a middle value, but if there’s is small variance (all 3 numbers are around 0.2, say) then you go for a hig h value

eager galleon
#

it's uniform distribution, so the variance is known to be 1/12

#

var(A - B - C) = 3 * 1/12

fresh abyss
#

Why did you subtract the variance of the three?

midnight plankBOT
#

@fresh abyss Has your question been resolved?

midnight plankBOT
#
Channel closed

Closed due to timeout

Use .reopen if this was a mistake.

#
Available help channel!

Send your question here to claim the channel.

Remember:
Ask your math question in a clear, concise manner.
Show your work, and if possible, explain where you are stuck.
After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!

Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.

still cove
midnight plankBOT
still cove
#

can someone explain why can we write Y1 = -2X1 +X2
AND Y2 = X1 +X2

#

like why they didnt give any explaination for that

fallow scarab
midnight plankBOT
#

@still cove Has your question been resolved?

midnight plankBOT
#
Channel closed

Closed due to timeout

Use .reopen if this was a mistake.

#
Available help channel!

Send your question here to claim the channel.

Remember:
Ask your math question in a clear, concise manner.
Show your work, and if possible, explain where you are stuck.
After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!

Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.

ember sage
#

how do u determine the power of x's n the answer

heady plume
#

Starting with the right.

Rightmost: Remainder : 55
Next: x^0 [constant term] : 27
Next : x^1 : 11
Next : x^2 : 4
Next : x^3 : 2

heady plume
#

if you start with right and move in that order, yes

ember sage
#

ok thanks

#

.close

midnight plankBOT
#
Channel closed

Closed by @ember sage

Use .reopen if this was a mistake.

midnight plankBOT
#
Available help channel!

Send your question here to claim the channel.

Remember:
Ask your math question in a clear, concise manner.
Show your work, and if possible, explain where you are stuck.
After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!

Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.

ancient sonnet
#

hey hey, quick question. is this the right series of formulas for determining a riemann sum?

sharp coral
#

that is mostly correct for calculating a left- or right- riemann sum with equal-length subintervals

#

but you need to be consistent with the sum variables (the variable should be i, and the upper bound should be n)

#

and a left- riemann sum goes from i = 0 to n-1, whereas a right- riemann sum goes from i = 1 to n

ancient sonnet
#

oo o ok ty, ill fix that then

#

very much appreciated!!

#

.close

midnight plankBOT
#
Channel closed

Closed by @ancient sonnet

Use .reopen if this was a mistake.

midnight plankBOT
#
Available help channel!

Send your question here to claim the channel.

Remember:
Ask your math question in a clear, concise manner.
Show your work, and if possible, explain where you are stuck.
After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!

Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.

twilit field
#

I'm trying to integrate this by converting it into polar coordinates

twilit field
#

Getting really strange limits

#

I'm getting $\int_{0}^{\pi} \int_{0}^{\sin(\theta)}d(r)d(\theta)$

grand pondBOT
#

What a wonderful world!

twilit field
#

What's wrong

visual tiger
#

I can see a few things

#

first of all why isn't it rdrdtheta

#

second of all how did you get the bounds

twilit field
#

Why should it be rdrrdtheta

visual tiger
#

dxdy = rdrdtheta

twilit field
#

oh, it;s the jacobian

visual tiger
#

and can you explain the bounds

twilit field
#

Hmm

#

Oh right

#

okay

#

I see

#

The line r=1 is at at a constant distance from the origin

#

r=1

visual tiger
#

the line?

twilit field
#

Sorry, I mean the curve

#

so $\int_{0}^{\pi} \int_{0}^{1} r dr d(\theta)$

grand pondBOT
#

What a wonderful world!

sudden yacht
twilit field
#

yeah

#

so π/2

twilit field
visual tiger
#

this one works now

twilit field
#

Got it

#

thanks

#

This feels really sus

#

I'm getting

#

$\int_{0}^{\pi}. \int_{-1}^{1} r^3 dr d(\theta)$

grand pondBOT
#

What a wonderful world!

sudden yacht
#

Two things:

  • why from 0 to π?
  • r can't be negative
twilit field
#

I see

#

okay

#

I think I'll have to split it into 2 regions then

sudden yacht
# twilit field

If you draw that region (in cartesian coordinates) what shape do you get?

twilit field
#

A circle

sudden yacht
sudden yacht
twilit field
#

hmm and r

#

r goes from 0 to 1, right

#

so $\int_{0}^{2 \pi} \int_{0}^{1} r^3 dr d(\theta)$

#

right

grand pondBOT
#

What a wonderful world!

twilit field
#

so I'm getting $4 \pi ^4$

grand pondBOT
#

What a wonderful world!

twilit field
#

which feels sus

twilit field
#

huh

#

it's π/4

#

what am I doing wrong

twilit field
#

That's wrong, is it not?

#

nvm

#

Got it

sudden yacht
#

Sorry, I've just seen the messages rn

#

Glad you worked it out 💪

heady plume
#

:| the bounds for theta is [0, π)

sudden yacht
#

Mmh I don't think so

sudden yacht
twilit field
#

I feel like the bounds would be identical here

#

$\int_{0}^{2 \pi} \int_{0}^{1} \ln( 1+ r^2) dr dt$

grand pondBOT
#

What a wonderful world!

twilit field
#

Of course integrating this is a pain, but that's a different story

#

Thanks

twilit field
#

I know it's a standard result

#

but still

heady plume
#

rln(1 + r²) - 2r + 2arctan r

twilit field
#

oops

#

I forgot the Jacobian

#

Yeah, in that case pretty easy

heady plume
twilit field
#

Yeah

#

thanks

#

This is much more interesting

#

Here theta would vary from 0 to π/4 I think?

#

and r from 0 to 2

#

so $\int_{0}^{\pi/4} \int_{0}^{2} sin(\theta) + cos(\theta)$

grand pondBOT
#

What a wonderful world!

twilit field
#

Or is that wrobng

#

anyway, I have a class now, will get back to this afte that

#

thanks

#

.close

midnight plankBOT
#
Channel closed

Closed by @twilit field

Use .reopen if this was a mistake.

midnight plankBOT
#
Available help channel!

Send your question here to claim the channel.

Remember:
Ask your math question in a clear, concise manner.
Show your work, and if possible, explain where you are stuck.
After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!

Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.

worthy plover
#

how would you write this as a function?
'A taxi costs 6$ for the first 3 miles, with every mile after the third costing an extra $.20'

I got as far as y=.20x +6 but I don't know how to reflect the part that the taxi only costs $6 for the first 3 miles

teal sluice
#

y=.20(x-3)+6

#

for x>3

worthy plover
#

oh okay, thanks for the help for sure :]

#

.close

midnight plankBOT
#
Channel closed

Closed by @worthy plover

Use .reopen if this was a mistake.

midnight plankBOT
#
Available help channel!

Send your question here to claim the channel.

Remember:
Ask your math question in a clear, concise manner.
Show your work, and if possible, explain where you are stuck.
After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!

Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.

midnight plankBOT
dense harness
#

<@&268886789983436800>

midnight plankBOT
#
Channel closed

Channel closed due to the original message being deleted.
If you did not intend to do this, please open a new help channel,
as this action is irreversible, and this channel may abruptly lock.

frail heron
#

.close

midnight plankBOT
#
Available help channel!

Send your question here to claim the channel.

Remember:
Ask your math question in a clear, concise manner.
Show your work, and if possible, explain where you are stuck.
After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!

Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.

tidal turret
midnight plankBOT
tidal turret
#

Let $f: \mathbb{R}^4 \to \mathbb{R}^4$ be the linear transformation defined by
[
f(\mathbf{x}) = (x_1 - x_3, x_3 + x_4, x_1 + 2x_2 + x_4, -x_1 - x_4)
]
and let
[
\mathbb{H} = { \mathbf{x} \in \mathbb{R}^4 \mid x_1 - x_4 = 0 }.
]
Then, $\operatorname{Ker}(f \circ f) \cap f^{-1}(\mathbb{H})$ is equal to

Select one:

\begin{enumerate}[label=\alph*)]
\item $\langle (1,0,0,0); (0,0,1,-1) \rangle$
\item $\langle (1,0,-1,1) \rangle$
\item ${0}$
\item $\langle (1,0,1,-1) \rangle$
\end{enumerate}

grand pondBOT
#

938c2cc0dcc05f2b68c4287040cfcf71

tidal turret
brisk iris
#

Start in ker H

#

What’s ker H

zealous schooner
#

What is ker H?

#

H isn't a linear transformation

tidal turret
#

bro I am tripping hard as balls

tidal turret
tidal turret
tidal turret
#

I got it i got it bro

#

I got the idea

#

I got it

#

let me draw it

brisk iris
tidal turret
brisk iris
#

My nephews are screaming 🙀.
I meant what’s f-1(H). There’s no kerH

tidal turret
#

wdym?

#

ker(H)=<(1,0,0,-1)>

#

still has a kernel bro even if it's a subspace of R4

#

not that the kernel of H is relevant to the Que, though

brisk iris
tidal turret
#

Kernel = Nullspace

brisk iris
tidal turret
#

is same thing, wdym the term is restricted to linear maps

#

anyways is not like I care, in spanish is "Nulo" for both linear maps and subspaces

#

in English maybe they invent more words

brisk iris
#

By definition,

#

Let’s not debate this. It’s not relevant to your problem

tidal turret
#

yeah, let's continue let me draw my idea

brisk iris
#

Now, what’s f-1(H)

tidal turret
#

why start with the preimage

#

can we start with the kernel, null or w/e is called of the linear composition

brisk iris
#

Ok

tidal turret
brisk iris
#

Write f as a matrix.

tidal turret
tidal turret
brisk iris
#

yup

tidal turret
#

you know what is am doing?

#

fuck my English and my keyboard sucks ass

tidal turret
#

and the outputs i place as columns in a matrix bro?

#

mmm fuck

tidal turret
brisk iris
#

I'm sorry I just can't focus, too much noise. I'll be back in 10 to 15

tidal turret
brisk iris
#

Waiiit

#

I have a much faster way

#

Can you compute det(f)

tidal turret
brisk iris
#

Yeah

tidal turret
#

what about it

brisk iris
#

Can you compute it

tidal turret
#

,w det {{1,0,-1,0},{0,0,1,1},{1,2,0,1},{-1,0,0,-1}}

grand pondBOT
tidal turret
#

we have kernel of f with dim >= 1

#

,w rank {{1,0,-1,0},{0,0,1,1},{1,2,0,1},{-1,0,0,-1}}

#

kernel of f has dimension 1

tidal turret
#

do not leave after saying that blobcry

brisk iris
#

Sorry I thought it was not 0 give me a moment

tidal turret
#

,w Nullspace[{{1,0,-1,0},{0,0,1,1},{1,2,0,1},{-1,0,0,-1}} * {{1,0,-1,0},{0,0,1,1},{1,2,0,1},{-1,0,0,-1}}]

grand pondBOT
tidal turret
#

ker(fof)=<(1,0,0,0),(0,0,-1,1)>

tidal turret
#

my way or the highway

#

but atleast we verified ker fof is correct

midnight plankBOT
#

@tidal turret Has your question been resolved?

brisk iris
#

Hey, still there ?

tidal turret
#

ye

brisk iris
#

Ok, take a look at this

#

Your solution is ker(f²)

#

@tidal turret since you computed ker(f²)

#

You got your answer

tidal turret
tidal turret
tidal turret
brisk iris
#

You don’t

#

You don’t need it

tidal turret
# brisk iris

bro in this case finding the inverse of A doesn't work because det(f)=0 remember

#

. . .

brisk iris
#

Im not talking about this inverse of A

#

Its the pre image of H by A

tidal turret
#

yeah

tidal turret
#

C is canonical?

#

why not use E

brisk iris
#

Yes any basis will do

tidal turret
#

kerA is a subspace of ker A^2

tidal turret
#

you computed kernel of (f)?

#

broo

brisk iris
#

Yes

tidal turret
#

this seems ok

#

but you skipped the steps of finding ker(f) bro

brisk iris
#

Cause you can do that in a calculator right ?

tidal turret
#

sure but in the exam bro

tidal turret
#

like this bro, I fixed some things

brisk iris
#

In the exam you’re not allowed to use a calculator ?

tidal turret
#

only scientific

#

but finding ker f is simple

brisk iris
#

The calculations you have to do here is finding both kEr f and kEr f^2

#

But if you want to be time effective without a calculator, that’s not the way to go.

tidal turret
#

is so confusing bro

brisk iris
#

What is ?

#

There is a different (faster way) when you don't have a calculator

brisk iris
# tidal turret

If you look closely, you'll notice that answers b,c,d are included in answer a.

tidal turret
tidal turret
#

or yes?

#

no man, ker fof entirely contains ker f

#

ker(f) n H is a stronger implication

#

I mean

#

I am not even sure anymore

#

I messed up

#

I messed up

#

I messed up

brisk iris
#

Look

#

I love reasoning, much more than calculations. So I did a lot of reasoning, and they I do calculations when I have to

#

However

#

If you had to do this during an exam. You should do it differently

tidal turret
#

however what

brisk iris
#

You have to look at the answers, and test them

#

Do you want me to write how I would do that in an exam ?

tidal turret
#

usually exam is not multiple choice thoo

#

but i get your point

brisk iris
#

You start by testing answer a, because you notice that all other answers are included in a

#

If a) fails (which it won't), you move on to (b) or (d).

#

If both fail, it has to be (c)

tidal turret
#

,w kernel {{1,0,-1,0},{0,0,1,1},{1,2,0,1},{-1,0,0,-1}}

grand pondBOT
tidal turret
tidal turret
#

any vector in ker(f) does not satisfy the equation of the plane H bro

#

ahh is so confusing i think I messed up again

#

fuck my life

#

I think I get it tho

brisk iris
#

Noise again

tidal turret
#

x in ker fof iff f(x) in ker f
x in f^-1(H) iff f(x) in H

f(x) in H n Ker f
but H n Ker(f) ={0} only trivial intersection

#

ohh, I'm stupid

#

let me explain with drawing

tidal turret
tidal turret
#

it wasn't hard per se, it was just confusing

#

but naming f(x) = y clear things up

#

look if ker(f)=<(-1,0,-1,1)>

#

then f(-1,0,-1,1)=0, so if I create an alias for f(x), call it, f(x)=y
where x is (-1,0,-1,1) and y = 0

#

we want f(x) in H and f(x) in ker f
0 is in H and in ker f
but particularly
f(f(-1,0,-1,1))=0
so (-1,0,-1,1) in ker fof

brisk iris
#

Wait. You’re right but then the solution would be just ker f

tidal turret
#

solution is just ker f according to answers

brisk iris
#

Yeah

#

Ok

#

Do you see how to fix my picture ?

tidal turret
#

how

brisk iris
#

Wait

tidal turret
#

yeah exactly bro

#

catthumbsup 🤓

brisk iris
#

Sorry I really struggled to focus today

tidal turret
#

no worries mate, I enjoy math when I struggle

brisk iris
#

Too much screaming at home

tidal turret
#

take care of your nephew bro

#

time is the only thing that doesn't go back

#

I appreciate the help I couldn't have done it without u bro, it wasn't hard, it was tricky

brisk iris
#

I do. He screams of excitement while playing Fortnite, and I can’t leave the room cause Fortnite should be supervised

tidal turret
#

🤭 😂

#

seems like fun

#

I will close this, thanks everyone

#

.solved

midnight plankBOT
#
Channel closed

Closed by @tidal turret

Use .reopen if this was a mistake.

midnight plankBOT
#
Available help channel!

Send your question here to claim the channel.

Remember:
Ask your math question in a clear, concise manner.
Show your work, and if possible, explain where you are stuck.
After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!

Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.

oblique gyro
#

okay so how do i do this again can i just cancel the cosxcosy

white gate
#

I think you think too much

oblique gyro
#

well can you help me think less

white gate
#

Use the cos(x-y) and cos(x+y) formula

opal garden
oblique gyro
#

i did

#

but now what

noble hatch
#

what?

#

where

white gate
#

Where

chilly adder
#

the direction is kind of correct if im following it right

oblique gyro
#

it’s cosxcosy+sinxsiny
/
cosxcosy-sinxsiny

oblique gyro
white gate
#

Divide numerator and denominator by cosxcosy

#

And that's it

chilly adder
#

$\frac{1+\tan x\tan y}{1-\tan x\tan y}=\frac{1+\frac{\sin x}{\cos x}\frac{\sin y}{\cos y}}{1-\frac{\sin x}{\cos x}\frac{\sin y}{\cos y}}=\frac{1+\frac{\sin x}{\cos x}\frac{\sin y}{\cos y}}{1-\frac{\sin x}{\cos x}\frac{\sin y}{\cos y}}\times\frac{\cos x\cos y}{\cos x\cos y}$

#

bruh

quiet parcel
#

bro had patience to write all that

#

mad respect

chilly adder
#

ok yeah

grand pondBOT
#

@chilly adder

chilly adder
#

this what i meant

#

this is "reverse-expanding" the angle sum identities if that makes sense

noble hatch
#

@oblique gyro have you solved any of your hw questions yourself? cause ive seen your previous ticket and it might be better for you to work on some easier problems

oblique gyro
#

what..?

#

i’m confused is this shade like

noble hatch
#

no not really

chilly adder
#

nothing is shady

#

unless

white gate
#

bull's shade!

noble hatch
#

tl:dr dont bite off more than you can chew

white gate
#

tl;dr start easy

chilly adder
#

tl;dr bruh moment

opal garden
#

tl;dr hi

oblique gyro
#

idk what u being shady for saying start easy as if i haven’t already started easy? i wouldn’t be working on these had i not done easier things before

chilly adder
#

well then

#

is your question answered

oblique gyro
#

like i’m confused on what this mentality of struggling on a problem equating to dropping the problem itself

chilly adder
#

i continued your direction

#

here

opal garden
noble hatch
#

not trying to be hurtful here btw

white gate
noble hatch
#

just work up in difficulty a bit slower

chilly adder
#

sometimes occam's razor works

opal garden
#

we belive in you Jayiee!

oblique gyro
chilly adder
#

different questions regardless

oblique gyro
#

and mind you idk why @chilly adder decided to jump in to throw shade

#

like let’s keep it civil

chilly adder
#

what did i do?

white gate
#

Shade bleakkekw

chilly adder
#

im not even white wdym

#

i think i answered your question

opal garden
#

Can you speak clearly?

white gate
#

!topic

midnight plankBOT
#

Please read the channel description before posting, and stay on topic.

chilly adder
#

yes your approach of writing tan into sin/cos is valid

#

if you continue it this way

#

but what we recommend here is to go with the approaches that come to your mind the first time

#

sometimes the most intuitive approaches outshine some complicated manipulation

#

especially in these

white gate
#

Wtf why are there so many bots recently

#

Today i met like 3 of them here

formal blade
chilly adder
#

lmao damn

#

to be fair

opal garden
chilly adder
#

the one who asked the question started accusing people out of the blue

formal blade
fathom onyx
#

"Could you phrase that a little more clearly?" would be a nicer way of asking that question perhaps

white gate
#

Can we just stop here please

chilly adder
#

right

oblique gyro
formal blade
opal garden
chilly adder
#

it is you who pressed on

formal blade
#

You don't need to pester them so much about their problem choice.

white gate
#

oh boy.

formal blade
#

You can say it once and let them choose to take or leave your advice

chilly adder
#

lmao.

oblique gyro
formal blade
#

No need for this to be drawn out

fathom onyx
#

On track - Does what Shirihan said help you @oblique gyro ?

formal blade
#

How about ya'll move on to the problem at hand rather than pedagogical meta-advice?

opal garden
#

!topic

midnight plankBOT
#

Please read the channel description before posting, and stay on topic.

white gate
oblique gyro
oblique gyro
formal blade
#

Okay good, lets get back on track.

#

Might help to repost the question down here.

fathom onyx
#

!repeat

#

er

formal blade
#

And maybe where you left off with what you understand too ofc

chilly adder
#

rambling where?

fathom onyx
#

is there a bot command to repeat the question?

formal blade
chilly adder
#

okay

chilly adder
oblique gyro
#

anywayy

formal blade
chilly adder
#

well

white gate
#

Answer:

  • Expand numerator and denominator of LHS
  • Divide numerator and denominator by cosxcosy
chilly adder
#

answering the exact question asked

#

yes you can cancel cosx cosy

#

assuming that gives you the desired result

white gate
#

Note:

  • The idea of dividing cos to obtain tan doesn't only appear in this problem, it is more common than you think.
  • Simple extra homework as an example:
    Given tan(x) = 3/4. Calculate A = [sin(x) + cos(x)]/[3sin(x) + 2cos(x)]
#

In fact, this idea is so common that it can expand all the way to very advanced problems you can meet in the future (particularly calculus)

#

But that's a different topic for now

midnight plankBOT
#

@oblique gyro Has your question been resolved?

#
Channel closed

Closed by @oblique gyro

Use .reopen if this was a mistake.

midnight plankBOT
#
Available help channel!

Send your question here to claim the channel.

Remember:
Ask your math question in a clear, concise manner.
Show your work, and if possible, explain where you are stuck.
After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!

Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.

umbral sparrow
#

am i right with C here?

midnight plankBOT
rocky storm
#

explain your thought process

dusty portal
midnight plankBOT
umbral sparrow
#

but i got C

dusty portal
umbral sparrow
#

i used the law of cosine

dusty portal
umbral sparrow
#

<@&286206848099549185>

dusty portal
#

What is this for?

round parcel
#

If you want to check it yourself, you can also use the law of cosines again and fill in all the values this time (including 81.325) and see if the sides equal each other.

#

If you do that, please say something like 6^2 = 5^2 + 3^2 - 2(5)(3) cos(93.82 degrees) or something.

#

That way, we can check to see if you have the right idea.

midnight plankBOT
#

@umbral sparrow Has your question been resolved?

midnight plankBOT
#
Channel closed

Closed due to timeout

Use .reopen if this was a mistake.

#
Available help channel!

Send your question here to claim the channel.

Remember:
Ask your math question in a clear, concise manner.
Show your work, and if possible, explain where you are stuck.
After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!

Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.

wind inlet
#

I have to find the non-permissible values for x. This is what I got, but in the answer key, it's π/2 + 2πn, nEI. Why's that..?

fallow scarab
#

show the answer key

wind inlet
fallow scarab
#

probably typo then unless the question asks for something else

wind inlet
#

Oh shoot, I just checked, and the teacher made some corrections in the answer key. I got a picture, but didn't correct it on the paper

#

It is + πn, ye

#

Thanks!!!!

kindred dagger
#

What does $n \in \mathbb I$ mean?

grand pondBOT
#

King Leo

kindred dagger
#

Like, what is the set I

wind inlet
#

N can be any integer

#

.close

midnight plankBOT
#
Channel closed

Closed by @wind inlet

Use .reopen if this was a mistake.

midnight plankBOT
#
Available help channel!

Send your question here to claim the channel.

Remember:
Ask your math question in a clear, concise manner.
Show your work, and if possible, explain where you are stuck.
After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!

Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.

last slate
#

Let A and B be subspaces of X,then A $\cup$ B might not be a sub space of X.

grand pondBOT
last slate
#

Why is this the case?

#

nvm

#

.solved

midnight plankBOT
#
Channel closed

Closed by @gleaming geode

Use .reopen if this was a mistake.

midnight plankBOT
#
Available help channel!

Send your question here to claim the channel.

Remember:
Ask your math question in a clear, concise manner.
Show your work, and if possible, explain where you are stuck.
After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!

Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.

last slate
midnight plankBOT
last slate
#

True or false

#

(k)

#

Oen min

#

$c_1(x-1) +c_2(x-1)^2+c_3(x-1)^3 = b_1x^3+b_2x^2+b_3x^2+b_4x+b_5$

grand pondBOT
last slate
#

And when I expanded the left side

#

I got

#

$c_3x^3+(c_2-3c_3)x^2+(c_1-2c_2+3c_3)x+(c_2-c_1-c_3)$

grand pondBOT
last slate
#

.close

midnight plankBOT
#
Channel closed

Closed by @gleaming geode

Use .reopen if this was a mistake.

midnight plankBOT
#
Available help channel!

Send your question here to claim the channel.

Remember:
Ask your math question in a clear, concise manner.
Show your work, and if possible, explain where you are stuck.
After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!

Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.

fierce canyon
#

when x=-1 y=2.5 when x=0 y=4 when x=1 y=7 when x=2 y=13 find the relationship between x and y

dusty portal
#

I suppose find the first, second, and third differences between the pairs?

fierce canyon
#

srry i wasnt on discord

dusty portal
#

So we have the first differences as 1.5, 3, and 6. Correct?

fierce canyon
#

yeah

fierce canyon
dusty portal
fierce canyon
dusty portal
fierce canyon
dusty portal
#

Now that I see it, I don't know what to do with this information.

fierce canyon
#

o

#

<@&286206848099549185> ?

#

<@&286206848099549185> pls

raven abyss
#

can you state all info given

vast ginkgo
fierce canyon
vast ginkgo
#

what happens to the difference for each increase in x

fierce canyon
vast ginkgo
#

yes

ancient plank
#

I've plugged it into desmos and found that it's cubic polynomial

vast ginkgo
#

what expression doubles each time x increases by 1

fierce canyon
vast ginkgo
#

like what type of function can double its value every 1 x

novel flax
#

the successive difference of the terms are in geometric progression

#

1.5, 3, 6...

fierce canyon
vast ginkgo
#

hint it's an exponential equation

vast ginkgo
#

that's the factor for every x

novel flax
#

so its general term would be given by

vast ginkgo
#

now what's the difference at x = 0 (to x = 1)

vast ginkgo
#

that would be considered your base change/increase

#

yes

#

now you can get 3(2)^x

#

for each increase

#

at x = 0 this will be 3

#

what do you have to add to get y = 4

fierce canyon
#

1

vast ginkgo
#

yep

#

that's your equation

fierce canyon
#

but why multiply by 3?

vast ginkgo
#

because 3 is the base change

#

3(2)^0 = 3(1)
3(2)^1 = 3(2) = 6
3(2)^-1 = 3/2 = 1.5

#

basically the value it should be at zero

#

it's just used to scale the exponential function

#

to the correct values

fierce canyon
vast ginkgo
#

i guess better to say initial value

#

the y intercept of an exponential function is always the coefficient a in a*(b^x)

#

a in this case is 3 because we start with a difference of 3

#

as x increases, this doubles

#

as x decreases this halves

#

because of 2^x

#

the difference still follows the points you gave above
from x = 0 to 1
3*2^1 - 3*2^0 = 3*2 - 3*1 = 6 - 3 = 3
from x = 1 to 2
3*2^2 - 3*2^1 = 3*4 - 3*2 = 12 - 6 = 6

#

(the +1 would cancel out since you're subtracting anyway)

fierce canyon
#

o think i understand it now tysm

#

.close

midnight plankBOT
#
Channel closed

Closed by @fierce canyon

Use .reopen if this was a mistake.

midnight plankBOT
#
Available help channel!

Send your question here to claim the channel.

Remember:
Ask your math question in a clear, concise manner.
Show your work, and if possible, explain where you are stuck.
After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!

Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.

wind inlet
#

I'm trying to understand how I solved his question. I have no clue how the + cos 2x in the denominator changed to smth I'm not even able to understand where I got from💀

white gate
#

the actual thing that changes is cos4x

wind inlet
#

Right... But I'm not sure what I did in the third step?

#

In the denominator

white gate
#

it's factorization

#

if you imagine in your head that u = cos 2x then the denominator becomes 2u^2 + u - 1

wind inlet
#

I think I get it

#

Thank you!!!!

#

.close

midnight plankBOT
#
Channel closed

Closed by @wind inlet

Use .reopen if this was a mistake.

#
Available help channel!

Send your question here to claim the channel.

Remember:
Ask your math question in a clear, concise manner.
Show your work, and if possible, explain where you are stuck.
After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!

Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.

midnight plankBOT
gaunt jetty
#

,, \sum_{k=1}^n 2^k \ne 2^n

#

am i misunderstanding something in what you are writing?

grand pondBOT
gaunt jetty
#

You are erasing the sum entirely

#

and resolving it to just 2^n

#

how did you go from orange to green here

midnight plankBOT
#

@teal rover Has your question been resolved?

#
Channel closed

Closed by @teal rover

Use .reopen if this was a mistake.

#
Available help channel!

Send your question here to claim the channel.

Remember:
Ask your math question in a clear, concise manner.
Show your work, and if possible, explain where you are stuck.
After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!

Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.

wet grail
#

hi do people in here know how to do boolean?

midnight plankBOT
kindred dagger
wet grail
#

X'Y' + Y'Z + XZ + XY + YZ'

rose trout
#

What is the task?

kindred dagger
wet grail
#

i'm stumped by the x'y' + xy

rose trout
#

Well first off Y'Z + XZ + XY have redundancy

#

The term Y'Z is redundant, so you can drop it.

Then, you can do it again with the last three terms.

wet grail
rose trout
#

No.
You can go from
X'Y' + Y'Z + XZ + XY + YZ'
to
X'Y' + XZ + XY + YZ'

Then use redundancy on the last three terms to drop another term (XY).

#

I don't think it simplifies to less than 3 terms

#

At least not with just OR, NOT and AND operators.

wet grail
#

and then i keep going till i have one left?

#

sorry my teacher hasnt taught me this yet

rose trout
wet grail
#

oh

#

i didnt read that

#

so it would just be X'Y' + XZ + YZ'

rose trout
#

Yeah I don't think you can do much better afaik

wet grail
#

A’BC + AB’C + ABC’ + ABC

Can you help answer this one as well

rose trout
#

You can kind of factor things out a bit

#

For instance, the last two term can be "factored" as AB(C + C')

wet grail
#

but i dont know how it becomes AB(C + C')

rose trout
#

ABC’ + ABC = AB(C' + C) = AB

#

You can see it as having the form XY + XY'.

#

This always simplifies to just X

#

Since it's telling you that the value of Y "doesn't matter"

wet grail
#

Y + Y' = 1?

#

how about A'BC + AB'C

Would it be C(A'B) + C(AB')

rose trout
#

You can see it like that, but it doesn't simplify as much

wet grail
rose trout
#

You can factor again with the second term

#

So

#

A'BC + AB'C + AB
A'BC + A(B'C + B)

#

Then what do you think B'C + B is ?

wet grail
rose trout
#

Hmm not exactly

#

You can try and do a mini truth table for it

#

If B=C=0, then B'C + B = 0
If B=1, C=0, then B'C + B = 1
If B=0, C=1, then B'C + B = 1
If B=C=1, then B'C + B = 1
What does the expression behave like then?

wet grail
#

or function

#

would it be B + C

rose trout
#

Yes

#

So that means that you get A'BC + A(B+C) = A'BC + AB + AC

#

Then what do you get if you factor B out of the first two terms?

wet grail
#

B(A’C + A + AC)?

#

B(A’C + A) + AC

rose trout
#

Yes

#

And then what does the brackets become

wet grail
#

A + C

#

BA + BC + AC