#precalculus
1 messages · Page 215 of 1
prefect
a little
i know
logging it
removes the
variable from the exponent
like pulls it down ?
aight
u dont need logs to solve this do you?
i don't think so
just equal exponent rule thing
i'm completely lost maximo, still can't figure out
$(2^2)^{x^2} = 2^{2x^2}$
AMD:
$2^{2x^2} \times 2^{5x} = 2^{3}$
AMD:
doesn't matter lol
ahh so it's your preference ?
yeah sure
aight
32 = 2^5
and 5 = 3 + 2
so we can just add the exponents together
and put it over the same base
2^2 * 2^3 = 2^5
see
care to throw up that wonderful text
let's just look at the left hand side of the equation now.
$2^{2x^2} \times 2^{5x} $
AMD:
$ = 2^{2x^2+5x}$
AMD:
because you add the exponents together
ahh we can combine
okay
and we can do this because we share the same base
is that correct
AMD:
the bases are the same
so if 2^5=2^x what is x
0 = 2^2x2+5x - 2^3
(that x has nothing to do with the question just an example)
$ 2^5=2^x$
Fishraider:
what is x
Fishraider:
so what is 3 equal to
lol
😦 lost me
Fishraider:
Fishraider:
yes
YES!!
but only over the reals
cmon amd
so if you try that with your equation
x = 3
no nono
that's what I think s/he is doing anyway
based on the examples you gave me I am assuming whatver my x is on one side it's reflected on the other
but i feel like that isn't right
$b^(n)=b^(5+2)$
piece:
wtf
I think you use the swiggly one
eh just nvm me i'll lurk
ok it might be easier to explain if you use log, do you know what log is @maiden igloo ?
2^(x²+2x+1) = 2^-1
idk if this example could help but this is what got one of my friends to understand how it works
still messed up 
Nightingale:
and you know that
$b^n=b^x$
piece:
when n=x
I think subi is long gone
do you know what log is
i do know
just log 2 both sides
nice
I realized that
it was
3 2x^2+5x
I kept thinking we had to do something with the bases
so i got confused
But i understand now that the example you showed me
$2^x=2^n$
Subi:
is saying
x = n
which are my exponent values
so set
x = n whatever that is and in my case was
yes
$ 2^3= 2^{2x^2+5x}$
so what's the answer you got
Subi:
-3 , 1/2

nice
goodjob
but dinner timw
ill be back
i appreciate you guys
a lot
im trying to get better
dont give up and you'll be fine
if the bases are different but they can turn into the same you can do that
like 4^x = 2^2x
$4^x=2^{2x}$
piece:
ez
ok piece do want to try a problem relating to this? It's not too difficult but I'll just put this here cause i came up with it like a minute ago
$b^{2k}=(-b)^{k^2+1}$
Fishraider:
its 4am so cant guarantee ill be able to solve
lemme get up and grab a piece of paper
you gonna solve for k or b?
k
2 unknowns
if k^2+1 is even then there is
figured but idk how to get there without just thinking
if you square (-2)^even then it's 2^even
but you dont know if it's odd or even
@unique hill if k^2+1 is even, k=1 k=-1 but -1 doesn't work so k=1
and k^2+1 is indeed even because 1+1 is even
the equation basically becomes b^2=(-b)^2
when k=1
I have two more question , the first one I just wanna confirm if im understanding the problem correctly
which is this
Information is given about a polynomial f whose coefficients are real numbers.
Find the remaining zeros of f .
Degree 5; zeros: -4, i, 5 − 3i
I said the remaining zeroes were -4 , i ,-i , 5-3i , 5+3i
Can u send a picture
Yes sir
Oki
don't need to list all 5
you talking to me
the remaining (2) zeroes in Q11 would just be the:
-i and 5 + 3i
he's doing prev question
Okay so i figured it was those for question 11
it just seem so simple
so thought it was wong
wrong*
I got 12 btw
the demon question
I skipped cause I was struggling is this one
that info layout is horrid
3 is a zero with multiplicity of 2
i is also a zero
(2+i)2
but why is I not listed with the zeroes
(2+i)^2
i thought it would be

(x-3)^2
they separated the list with ;

Can someone walk me through or point me to resources to explain this better
Khan academy
it uses the idea as the previous questions
The degree should reflect the amount of zeroes ... is this correct
conjugate root theorem
gotta look that up
if a+bi is a root, then a-bi is a root, assuming the polynomial has real coefficients
its pretty much exactly the same thing as what you just applied
because (a+bi)(a-bi) = a^2 + b^2 so it must have the conjugate so the imaginary parts can cancel out
yeah
wait im pretty sure complex numbers are not precalculus
Ain't it prealgebra
for my curriculum, calculus is taught before complex numbers
Complex nums is College algebra
But I don’t recall these theorems
I’ll openly admit I didn’t try as hard as I should have in the past and I’m obviously paying for it now , but I’m willing to go through that now
Cause I need this to be where I wanna be
i havent touched on complex numbers
What math are you in
as in?
so
complex numbers are like algebra 1 wtf
like how else do you solve x^2+1=0
no i'm just saying how do you do calculus without knowing what i is
x^2 = -1
oh square root of negative
give ...
i know it's like i or something
i think
+-i
conjugate root theorem says
if $(x - (a + bi))$ is a root of a polynomial with real coefficients, then $(x - (a - bi))$ must also be a root of the polynomial
AMD:
@fleet yew in response to ur comment, ik what i is but havent done anything with it
all ik is 1/i = -i
and stuff i did in calculus has no use of complex numbers
@fleet yew factor not root
I am referring to my question
I thought Degrees were connected to the zeros
for exmaple
Degree 3
zeroes 1, 2 , 1+i
sorry
Degree 4 zeroes 1, 2,1+i
i would assume it's the conjugate paiur
pair*
But here
the Degree is 3
If you count multiplicity, then there's exactly as many zeroes as the degree
Good morning Ann
I am aware of it for determining if
If the polynomial has real coefficients, then 1-i is a root as well
Oh, but you said it's degree 3. So, the polynomial must not have real coefficients
Here
Form a polynomial f (x) with real coefficients having the given degree and zeros. Show your work! Degree 4; zeros: 3, multiplicity 2; i
Oooooooo
wth
I kept reading it like this
Degree: 4
Zeroes:3
Multiplicity:2
i
So multiplicity is apart of the zeroes
A zero also has a multiplicity, yeah
is i not apart of the zero ?
question
(2)^1-x = (5)^x
solve exactly for x then evaluate your solution rounding to 3 decimals
why cant I log both sides and perform simple algebra?

opps
i.e. $2^{1-x}=5^x$
Maximo:
its that one
ok
I forgot parentheses
they aren't the same base
lmfao
the problem is you can't because theyre not the same base
what can be done though is using one of the log rules
$log(a^b)=blog(a)
$log(a^b)=blog(a)#
$log(a^b)=blog(a)
$
fuck
Maximo:
power rule?
yep
okay
do I apply the power rule to both sides of the equation?
I just solved the previous problem
using the same rule
(3)^(2x+5) = 54
I did it different way
(log 54 )/ (log3) = 2x+5
also that did not make sense when you said 3*18
because 3^(2x+5)= 3*18
basically what you're telling me is that
I can equate (2x+5) to 18?
Maximo:
RHS simplifies to 3 + log_3(2)
oh
\log
thanks ann
oh hi there
ill remember for next time
last question before i go to bed. Dealing with these real world problems as such , I get confused with what data goes where
Between 12:00 PM and 1:00 PM, cars arrive at a bank’s drive-thru at the rate of 12 cars per hour (0.2 car per minute). The following formula from statistics can be used to determine the probability that a car will arrive within t minutes of 12:00 PM.
F (t) = 1 − e −0.2t
Determine the probability that a car will arrive within 10 minutes of 12:00 PM. Round to two decimal places as needed.
I can be patient let's help subi first
No lets finish your question
okay sure
okay thank you
so my question (2)^(1-x) = (5)^(x)
@maiden igloo
yeah it is
oh constant
I believe this is an expotential growth function
yes
(2)^(1-x) = (5)^(x)
three of these four pairs of parentheses are redundant
ann you're very nitpicky haha
is it not simply F(10)? @maiden igloo
uh
oh
Idk
within
I am trying to understand how to break this down
mirrion go to a questions channel ill help you
hmm
which channel
any one not occupied
okay thank you see you there
do i put 10 in for F(T)
It would be negative
and put 10 where t is
correct
Are you sure F(t) is written correctly
let me send pic
ok
so thats
different
now please tell me
i have never taken probability
but its between 0 and 1?
yes
ok
yes it should just be F(10)
let me work it out
86.4%
How do you graph a 3d plane
Like
Its easy to plot the points by just finding intercepts
But i dont know how to draw the plane
Hmm i thanks
I tried that already i still couldnt get it
What im thinking of right now is just make up line equations in two dimensions then just somehow piece them together
Is there a way for me to donate to you guys
THANK YOU !
Guys I'm supposed to use a calculator to solve for theta on the interval [-90deg,90deg]
for Sin(theta) = 3/4
I did arcsin(.75) and got 48.5903 deg
48.6 (rounded) degrees is one of the solution
and I also got 131.4096 deg from subtracting 48.6 from 180 deg
since sin i positive in q2 right?
yep
from a neg, you go clockwise along the ASTC circle
so from 0 to 90 degrees, u go anticlockwise
but from 0 to -90 degrees, u go clockwise
+369
360
I think would give coterminal angle
That is the same
One of the smart guys can verify
There's only one solution in that range, the one your calc gave you
hmm i see
thanks guys
90 -41.4
that's arcsin 3/4
Would that be the coterminal
Ahh okay I’m dumb
Got it
Thanks for all the help guys
I hope this discord is around for the next 2 years help me through college
Goodnight
gn
Last question for the day if anyone is still here
how would you go about getting the equivalent of 6sinxcos(5x)
would it be
3sin(6x)+3sin(4x)
?
"the equivalent"?
are you talking about double angles?
no that's not what nightingale means
$\sin(a) \cos(b) = \frac12 (\sin(a+b) + \sin(a-b))$
Ann:
thx for typing it in texit
a and b are the respective angles
how would you get angles from something like this

doesn't look like I have much to work with, not much that i can see anyways
first focus on the ones inside the brackets
ignore the 1/2 for now
so just $sin(a+b)+sin(a-b)$
sin(5x+x)
Nightingale:
?
Nightingale:
all I can think of is
6sin(X+5X) + sin (X-5x)
6sin(6x) + sin(-4X)
6sin(6x) - sin(4X)?
minus in the middle
you're using a different formula now
becuz a and b are switched
o ok
so to avoid negative in bracket
formula was different and sign was switched
?
Nightingale:
that is just 2 multiplied by the whole thing
ok now, u know that a=5x and b=x
you have everything u need to know
sub into $2cosAsinB=sin(A+B)-sin(A-B)$
Nightingale:
oh right cus we multiplied first in the paranthesis
so now what's your LHS and RHS
2cos5XsinX
sin(6X)-sin(4x)
I'm not confused by the question, what do you mean what's on my left hand side and right hand side.
there's an equal sign in between them
cuz you subbed in a and b into the formula which has an equal sign in the middle
so LHS=2cos(5x)sinx and RHS=sin(6x)-sin(4x)
right
Well it's the first time I've seen something like that, but yes we have a LHS and RHS
and they're set to equal each other
now what's the question asking?
Which of the sums is equivalent to 6sinxcos(5x)
my best guess would be 3sin(6x)-3sin(4x)
but our RHS is completely different
ever since we dropped the 3 and moved onto a new formula
so i'm confused
since u found out 2cos(5x)sinx, u can times 3 on the other side since the question is asking for 6cos(5x)sinx
ohhh
typo
okok
no worries
lim(f(x)) = -inifinity
(x -->+inifnity)
i have to prove this using the epsilon gamma method but i uh
yeah i dont really get it
What is the question
wait nvm they're being as vague as ever in the book
just want me to write it in epsilon-delta form
aight then
good morning
good morning
,rotate
Help with number four PLease
IM SO OCNGUSED
try different points to see how it looks
uhhh what
Thats not
I mean how do I space it out
And what intervals
And when use period
ok the center is zero
and you have all that room on the right to get to 2 pi
so space it as you will but utilize the room wisely
So i spaced it out an it is PI OVER FIVE
WHAT
ALSO THE PERIOD IS FOUR PI
what does that mean
how is im so confused right now
ok
because listen if spaced OUT evenly
lets take it slow
21
o
I Wrote two pie now what
ok infucekd up
its only 20
so i wrote two pied at the end
And wrote pie in centrez
ok no waht
then just earase and rewrite it
oh shet i fucked up
until you can fill in the lines
but the frequences
the question didn't ask for that
all its asking is for you to plot the graph in the given interval haha
i can’t
and theta = pi/2
ghe graph
ok
wait
so
for two pie
Is just cos pie
so
thats neg one
how on gods green earth do i do 3pie over Two
unit circle
looks fine
if i fail i will blzme you but i thinkz you did it right sonidk
BRUH
HOW THE FUCK
😗
,rotate 270
!rotation
dawg i taught you how to do it
you just need to plot points until ou find the shape
listen my guy i got some sleep to catch up on
LIKE ONE AND NEGATIVE ONE
think about it
plot points and figure out what the maximum and minimum y values can be
i like you
😄
How do you do this? It's in an online worksheet
They didn't explain how
this too
@sturdy haven still need help?
think in reverse, think of an angle x between 0 & pi such that cos(x)=-1/2
two values I think?
yeah
can someone quick help me with this?
1 thing is that theta is in the 4th quadarant
yep
are you supposed to use a formula or something for this?
what's stopping you from just saying theta=-80.53
tbh we did this before corona/spring break and its been 3 weeks since we have done this so i completly forgot how lol
oh
and just plugging the value in
i think you're fine
ok
The perimeter of a stadium is an ellipse with major axis 640 feet and minor axis 549 feet. Find the distance between the foci of this ellipse.
giw di u di this?
how do i do this lol sorry
ok i need someone to walk me through this one i managed to solve my other problem
so i know the answers isnt 7pi/6 because of the restriction of inverse cos being between 0 <= x <= pi
so what do i do next?
well cos (pi+theta)=-cos(theta)
so cos 7pi/6 is -cos pi/6
and you can calculate that
also the answer would be 7pi/6 and another value if there wasn't that restriction, don't think 7pi/6 isn't right though
well back of the book we have answer and it says the answer is 5pi/6
and going through some website it says to use the refence angle
it is 5pi /6
but 7pi/6 is also an answer if the restriction wasn't there
do you know cos (pi+theta)=-cos(theta)
no i dont know thecos (pi+theta)=-cos(theta)
you could use that and change cos(7pi/6) into -cos(pi/6)
oh it's because of the unit circle
do you know the unit circle
yup
is that just a reference angle?
theta?
theta is a variable angle
if that's what you mean
theta is usally a variable referring to angles
and cos pi/6 is cos 30 which is sqrt3/2
that's also on the unit circle
since we are taking the arcos of -sqrt3/2 it's in the 2 or 3rd quadarant
but by the restriction it can only be the second one
which would be 180-30 degrees
150 degrees
did you know that cos (180-theta) also equals -cos theta?
nope i didnt know that
well it'll be hard to explain
well looks liek this math teacher missed out on alot of information in that case
have u learnt ASTC?
yeah
pretty sure ASTC covers that
draw a triangle
cant figure out how to start this
if someone can pm me. i know that i should use tan but i keep getting a negative number and not a big enough number
looks like the channel's taken
@slate oracle draw a diagram of the building and the shadow
For the measure(in feet) of the shadow and top of building.
angle between the end of shadow and vertical side of building from the person
Yes.
Tangent..?
that's correct
So then, tantheta= 100/230.. correct?
yes
And then we would move tan to the other side making the equation theta=tan^(-1)100/230
Right?
yep
So then, we would find the degree.. which is.. ~23.
Right..?
Would be estimate the degree or not?
if it's rounded to one decimal place, it's 23.5 degrees
it says to the nearest degree
Oh, sorry.
round to nearest degree
So it's 25 degrees..?
You said it's 23.5 which is 24.
no that's if its rounded to one decimal place
that's it, you've found the angle
yeah that's the answer
np
just make sure the 47 degree angle is clear
your diagram looks correct
I would use sin, which leads it to being sin35=x/59 which would make x=(sin35)(59). Then x would be 33.84 or ~34 meters.
Ye?
uh not sine
Then what..?
sohcahtoa?
cosine?
ok first, dont guess
ok
what's the trig ratio for cosine?
Uh. I don't know.
ok you're trying to find the height of the building right? excluding the radio tower
Yeah, which would be considered the opposite.
mhm, and you are given the distance of the person to the building, which is adjacent
Yeah
you need to find the opposite and you are given the angle and adjacent
so what trig ratios would u use?
uh okay, first tan 35 = opp/adjacent correct?
you follow?
the tan ratio is opp/adj, and you are given the adj
Yeah but not the oppo.
$tan{35}=\frac{height of building}{59}$
Nightingale:
Yeah
yes, you make the height the subject
So multiply everything by 59
@viscid thistle this channel's taken
Making the equation (tan35)(59)
?
@viscid thistle im waiting for someone to help me next
(tan35)(59)=~41
So then what would be doo
you have just found the height of the building, excluding the height of radio tower
the second part is find the height of building and the radio tower together
Ok


