#help-27
1 messages · Page 192 of 1
$n(A \cup B) = n(A) + n(b) -n(A \cap B)$
Percy
$n(A \cap B)=3$
Percy
I've been doing math for over 10 hours a day for the past week and I'm about losing my ability to remember anything lol
you know $n(A)$ and $n(B)$
Percy
us indeed
this is not like fancy or anything btw
Was I taught it? Probably! Do I remember it? Not at all lol
you just plop the sets together and then remove the ones in common because they'd be double counted
yeah yeah it's notation
Okok, I get the first three, now.. how does $n(A \cap B)=22$
ari
And how is the upside down and up cap related
Ok so it's 12 + 13 - 3
So n(A n B) is how many cards overlap
It doesn’t no
That’s union
My bad, I meant the cap the other way lol
So since n(A n B) is called an intersection, is there a name for n(A u B)
Union
Oh
NO
not the number
just A U B is the Union of a and b
It’s a set
Not a number
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✅
I did 9! to get the 2nd answer, I don't know where they are getting 90,720
<@&286206848099549185>

that should be right
9!
ohhh wait
i misread the right answer
It's okay, I'm sure we're all losing it a bit here
It's order doesn't matter tho right
i got 40,320
for 8!
Aaaaa
So what calculation gets 90720
uhh
362880÷4 =90720
thats divided by 4
why 4
if there's 2 E
that makes 8 selective letters
8! Should be the right answer I don't know how they are getting 90720
so like for a similar question, that also has 2 of the same letters in the word
cuz ur rearranging the letters
there's stil lgonna be 9 letters
So their wrong
I'm right
1 e doesnt disappear
yeah
9! should be right
thats canvas right
talk to your teacher maybe
wait
pause
Paused
8! Makes sense
it does
cuz no matter which e goes where
but it'd still be 9 letters
9!/4
n!/(n-r)!, where n is the total number of objects and r is the number of objects being arranged.
THERES 2 L'S
Sorry I can't read
ohhh
haha
Okok
So
9! ÷4!
It wouldn't be 4 factorial
no
it wouldnt
Why do they put a factorial in this example I'm looking at
One second
I'll send
ok
i have an example that might be easier
so 9 letters
2 repeat twice
9!/2!*2!
idk why did it in 2 factorials though
for the denominator
Yeah
After they end up using 2
but only 7 of the 9 change for each ig
so 9-2
Not the factorial of 2
well
whats
2!
2*1
2
2!=2
Yeah
OH
True
4! Is like 24
But that wouldn't make sense
lmaoo
yeah
they did it in 2 here though
2!*2!
OH
OHHHHH
OHHHHHHHHHH
Ok
Makes sense
I get it now
yep
so 9!/4
Thank you!!
ofcourseee

glad we figured it out
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GTO Incorporated is considering an investment costing $210,720 that results in net cash flows of $30,000 annually for 10 years. (PV of $1, FV of $1, PVA of $1, and FVA of $1) (Use appropriate factor(s) from the tables provided.)
(a) What is the internal rate of return of this investment?
(b) The hurdle rate is 8.5%. Should the company invest in this project on the basis of internal rate of return?
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I know the answer is D. But if x could be equal to 1 and -1 then how would i solve it
Because it's obvious that it can't be equal to +-1 or you are dividing by zero
So why did they say that
just so what they're saying is mathematically correct
Oh ok
cus expression wont have any sense otherwise like u said
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- tan(x)=2; pi <= x <= 2pi find sec(x)
- the points (3.5,-1) and (5.5,-6) are on the graph of a trig function what is the function that models?
- The average depth of water at the end of a dock is 16 ft and it varies 4ft in both up and down directions, caused by the tidal. The tide goes from low to high every 8 hours. The depth of water is at the average depth at 3 AM with respect to time t. Let t=1 corresponding to 1 AM
4)graph y=2tan(x/2-pi/3)+1 and y=1/2csc(2x+pi)+2
im confused on how to do all of these
would be helpful if someone showed me the answers and then explained since i need to turn them in soon
<@&286206848099549185>
anyone?
@fervent swallow
<@&286206848099549185>
hey
@torn bobcat Has your question been resolved?
hi
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Ugugucu
?
whats your question?
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A radio tower is located 400 feet from a building. From a window in the building, a person determines that the angle of elevation to the top of the tower is 30 degress
and that the angle of depression to the bottom of the tower is 24 degress
. How tall is the tower?
try drawing a picture, might help
@robust cape Has your question been resolved?
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hi
What progress have you made?
Are you aware of the Chinese remainder theorem?
i found x from the first eqn and substituted it in the 2nd so we get 7a+3 congruence 3(mod5) then from there I found a which is 5b+3 and now im confused what to do next
yes
should i substitute the value of a in the first eqn ?
what are you getting for x
7a+3
you can't just divide by 2
why
np
anyway it's probably most simple to do this by writing out multiples until you get the lcm of 14,15 60
or directly apply crt
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What is the mistake in this solution
,rotate
Khan academy
pic pls
your result is equivalent to b from power law for log
option C isn't the same as what you got
I know i just randomly picked it to see answer
Oohh
Right
Thx
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<@&286206848099549185>
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,rccw
oh sorry
dw
the radius is 5?
is the center of first circle is (8, 14)?
yeah
the radius is 4?
ohhhhh
center of circle number 2 is (4, 10)?
(4, 9.5)
ohhhh
yes
(12, 9**.5**)
ohhh okaay
when you count horizontally that's not the diameter
if you count vertically it's gonna be 9 units
Bro it’s 4
no bro
Why does it matter which way u count
Do u know what radius is
not this again
The easiest and most visible way to count for that circle is horizontally
When x = 0
Look at x = 0 and x = 8
That’s one full circle
For circle 2
Each of the circles are the same
try drawing the diameter when r = 4
the center would not be equidistant from the circumference
it would 4 units and 5 units
if you draw the diameter vertically, you get 9 units
this would mean that the radius is at 4.5 units on the y axis
on plotting the diameter horizontally with y axis as 4.5 we get the diamater as 9 units as well
this would mean that the original diameter of 8 units is not the diamater as its not the longest chord
Circle two starts at x 4 ends at x 12
Length is 8
Radius is 4
How is it that hard to understand
thats what i thought before as well
but then when i actually counted it it's not coming as 4 idfk why
The horizontal distance will ALWAYS be the same as the vertical distance if it’s a CIRCLE
ik ik
A circle has a definition
i thought it was 4 bro
but when i counted it's not coming well anyway
just take it as 4
i think it's probably a problem with how the image is coming on my screen idfk
yeah ik
if you look at the circle vertically its not actually from y = 10 to y = 18
there's a slight offset
but anyway
uhmmm
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@marble otter Has your question been resolved?
The first lampta should be 3/5
Ich denke hier macht es keinen Sinn, da die Funktion keine lokalen Extrema unter der Nebenbedingung haben kann. Angenommen du setzt die Lampta's ein, dann ist die Gleichung nur noch von einer Variablen abhängig
lambda btw
Die Gleichung wird also von einer Variablen unabhängig und somit ist die Bedingung, die du ansetzt trivialerweise erfüllt
Danke, du konntest ja auch deutsch?
vllt konnte ich das. aber lagrange zeug ist zu lange her
Musst du hier notwendigerweise Lagrenge anwenden?
Wie gesagt, es gibt keine lokalen Extrema. Denke deswegen macht das keinen großen Sinn hier
Sagen wir x1= x und x2 = y
was ist überhaupt die frage
Maximum vom 3x+4y unter 5x+7y = 35 nehme ich an?
!original
Please show the original problem, exactly as it was stated to you, with the entire original context. A picture or screenshot is best. If the original problem is not in English, then post it anyway! The additional context might still be helpful. Do your best to provide a translation.
Können x und y auch negativ sein?
ach komm das aufgabenblatt kann dir doch nicht nur so zufällige Symbole wie m=35 geben. da wird doch irgendeine aufgabenstellung draufsein
Danke, für das direkte Nachfragen. Wäre jetzt so schnell nicht drauf gekommen. Das x,y nicht negativ sein kann verändert einiges
also ist das hier unter dem Titel lagrange zeug oder lineare optimierung
was du auf jeden fall bisher überhaupt nicht hast einfließen lassen ist x>=0 und y>=0. das sind beides super wichtige bedingungen
aber ich weiß auch nicht mehr wie man das mit lagrange macht, sorry
also in der linearen Optimierung gibt es den simplex algorithmus im allgemeinen. Für R^2 ist der aber vollkommen overkill
hier könnte man das tatsächlich graphisch lösen
aber naja das sollt ihr vermutlich nicht tun
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are these matrices in echelon form or reduced echelon form or neither?
neither
what can you tell me about the properties of matrices in:
- echelon form
- reduced echelon form?
1 in principal diagona and zeroes below it (echelon)
1 in principal diagonal and zeroes both above and below it (reduced echelon
hm
not quite (in particular, the "principal diagonal" part is false)
here is a good definition of "echelon form" (not reduced)
so it doesnt need to be one?
principal diagonal does not need to exist in an echelon form matrix
wdym by that
principal diagonal to my knowledge is the items in a matrix in the same-numbered row and column
which is not relevant when we consider echelon forms
yea so it doesnt need to be one?
what is your definition of "principal diagonal" ?
well, consider the matrix as a rectangle, and then just scribble a line which joins the entries and looks the most diagonal-like out of all other possible lines you could have drawn
🤓
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I'm confused on how to go about solving this problem. I'm confused on the method/logic that I need to use to solve it
fI think t1 =6, t2=8, and t3 =1, but after that I am unsure. Do I just reuse the same numbers or am I suppose to do it in intervals
they're hinting at the fact that the concentration of coffee increases only when you're actually drinking coffee
it qould be like
g1 0<t≤6
g1 6<t≤6.5
g3 8<t≤8.5
g4 1<t≤1.5
well you need to have the times between the coffees also
g1 : 0 to 6
g2 : 6 to 6.5
g3 : 6.5 to 8
...
as for the 1pm, they're expecting you to use 24 hour time here
the final time for the day is 24
but I just wrote that?
what would be the time in between the coffee
oh
so that means it's
g1 : 0 to 6
g2 : 6 to 6.5
g3 : 6.5 to 8
g4 : 8 to 8.5
g5 : 8.5 to 1
g6 : 1 to 1.5
g7 : 1.5 to 24
is this correct?
you still need the 24 hour time here
what does 8.5 to 1 even mean numerically ?
are you going backwards?
that 4.5 hrs passed
well isn't it implied that time is going forward meaning it's going from AM to PM
there's no AM or PM with real numbers
so then what do i do for this
it's like you went back 7.5 hours somehow
and for this
1pm = 13 hours past midnight
not sure what you're saying here
I'm not sure what you're saying eitherabout the 8.5 to 1 thing
the problem is you end up with two different moments of your day which correspond to the same t-value
you can't distinguish 1am from 1pm like that
oh
so that's why they're using 24 hour time in this exercise
so instead ur saying write 13 and 13.5 to represent them as 1
which makes sense because on a 24 hour clock you can easily represent am and pm without labels
g1 : 0 to 6
g2 : 6 to 6.5
g3 : 6.5 to 8
g4 : 8 to 8.5
g5 : 8.5 to 13
g6 : 13 to 13.5
g7 : 13.5 to 24
So this is how it should be written, correct?
was just about to ask that lol
well y(t) [the function you're trying to find] is the concentration of caffeine in your body throughout the day
so how would i go about that? Do I just enter 30 for every time coffe is consumed and put a 0 when it isn't
well 0 when you're not drinking coffee sure
but if you reread the end of the paragraph, they tell you how much caffeine concentration increases while you're drinking coffee
0 : 0 to 6
40 : 6 to 6.5
0 : 6.5 to 8
40 : 8 to 8.5
0 : 8.5 to 13
40 : 13 to 13.5
0 : 13.5 to 24
????
that looks really wrong
I gtg for a bit
okay
Yeah 40 when drinking, 0 when not
You gotta correct where you put your 40's tho
oh it should be reversed
0 : 0 to 6
40 : 6 to 6.5
0 : 6.5 to 8
40 : 8 to 8.5
0 : 8.5 to 13
40 : 13 to 13.5
0 : 13.5 to 24
So I'm doing the second part rn which states
Assume that the half-life of caffeine in the blood is 4 hours and use the Forward Euler Method to find the concentration of caffeine in the blood over a 24 hour period. Use a step size of dt = 1sec and plot y(t) and g(t) on the same plot.
since it's half life I use:
$y(t) = y_0 e^{-kt}$
right?
arrow891
It's not like your g(t) is straight up 0
How do you know the solution looks like that
They're telling you to solve the equation numerically anyway
With forward euler
and from there I just plug and chug
t = 4 x 3600sec = 14400
y_0/2 = y_0 *e^k (14400)
and then solve for k
with half life an atom decays at an exponential rate
They told you the equation to find k if you know the half life already at the beginning
Yes
t is the 40, right?
Yeah
and that's it?
that seems to simple
also you said I gotta correct my g(t) cuz it's not "straight up 0" lmao
No your g(t) is good
ah okay
You were saying that y(t) should be a bog standard exponential
so then k ≈ 0.0753
But that's only the case if g(t) is always 0
oh
so I should solve this $y′ = −ky + g(t)$ which becomes $y=\frac{g\left(kt-1\right)}{k^2}+\frac{c_1}{e^{kt}}$
arrow891
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thre that into symbolab lol
What's going on with g(t) here
Again, they're not asking you to solve the equation by hand
Do you know what the forward euler method is ?
code?
yea
it's just euler's method formula
Yea run it on your computer
500 sounds a bit much
You only took 3 coffees which increase the concentration by 40 each
And the concentration only decreases after that
import numpy as np
import matplotlib.pyplot as plt
# Define constants
dt = 1 # Step size in seconds
t_half = 4 * 3600 # Half-life of caffeine in seconds
k = np.log(2) / t_half # Decay rate constant
# Define function g(t)
def g(t):
if 0 < t <= 6:
return 40
elif 6 < t <= 6.5:
return 0
elif 6.5 < t <= 8:
return 40
elif 8 < t <= 8.5:
return 0
elif 8.5 < t <= 13:
return 40
elif 13 < t <= 13.5:
return 0
elif 13.5 < t <= 24:
return 0
else:
return 0
# Define Forward Euler Method to solve the differential equation
def forward_euler(y0, g):
y = [y0]
t = np.arange(0, 24 * 3600 + dt, dt)
for i in range(1, len(t)):
y_next = y[-1] + dt * (-k * y[-1] + g(t[i]))
y.append(y_next)
return t, y
# Initial concentration of caffeine in the blood (mg/L)
y0 = 0
# Solve the differential equation
t, y = forward_euler(y0, g)
# Plot the concentration of caffeine in the blood and intake function g(t)
plt.figure(figsize=(10, 6))
plt.plot(t, y, label='Caffeine Concentration (mg/L)', color='blue')
plt.plot(t, [g(ti) for ti in t], label='Intake Rate (mg/L/hr)', linestyle='--', color='red')
plt.xlabel('Time (seconds)')
plt.ylabel('Concentration (mg/L)')
plt.title('Concentration of Caffeine in Blood over 24 Hours')
plt.legend()
plt.grid(True)
plt.show()
You forgot to change the g
Not unless I have a shift I guess lol
import numpy as np
import matplotlib.pyplot as plt
# Define constants
dt = 1 # Step size in seconds
t_half = 4 * 3600 # Half-life of caffeine in seconds
k = np.log(2) / t_half # Decay rate constant
# Define function g(t)
def g(t):
if 0 < t <= 6:
return 0
elif 6 < t <= 6.5:
return 40
elif 6.5 < t <= 8:
return 0
elif 8 < t <= 8.5:
return 40
elif 8.5 < t <= 13:
return 0
elif 13 < t <= 13.5:
return 40
elif 13.5 < t <= 24:
return 0
else:
return 0
# Define Forward Euler Method to solve the differential equation
def forward_euler(y0, g):
y = [y0]
t = np.arange(0, 24 * 3600 + dt, dt)
for i in range(1, len(t)):
y_next = y[-1] + dt * (-k * y[-1] + g(t[i]))
y.append(y_next)
return t, y
# Initial concentration of caffeine in the blood (mg/L)
y0 = 0
# Solve the differential equation
t, y = forward_euler(y0, g)
# Plot the concentration of caffeine in the blood and intake function g(t)
plt.figure(figsize=(10, 6))
plt.plot(t, y, label='Caffeine Concentration (mg/L)', color='blue')
plt.plot(t, [g(ti) for ti in t], label='Intake Rate (mg/L/hr)', linestyle='--', color='red')
plt.xlabel('Time (seconds)')
plt.ylabel('Concentration (mg/L)')
plt.title('Concentration of Caffeine in Blood over 24 Hours')
plt.legend()
plt.grid(True)
plt.show()
And there's one other problem now
better?
The time in g(t) isn't in seconds
You have to be coherent with your units
So you gotta multiply each boundary by 3600 in g(t)
on the x axis?
You chose t to be in seconds
nvm
But g(t) expects a time in hours right now
import numpy as np
import matplotlib.pyplot as plt
# Define constants
dt = 1 # Step size in seconds
t_half = 4 * 3600 # Half-life of caffeine in seconds
k = np.log(2) / t_half # Decay rate constant
# Define function g(t)
def g(t):
if 0 < t <= 6 * 3600:
return 0
elif 6 * 3600 <= t < 6.5 * 3600:
return 40
elif 6.5 * 3600 <= t < 8 * 3600:
return 0
elif 8 * 3600 <= t < 8.5 * 3600:
return 40
elif 8.5 * 3600 <= t < 13 * 3600:
return 0
elif 13 * 3600 <= t < 13.5 * 3600:
return 40
elif 13.5 * 3600 <= t <= 24 * 3600:
return 0
else:
return 0
# Define Forward Euler Method to solve the differential equation
def forward_euler(y0, g):
y = [y0]
t = np.arange(0, 24 * 3600 + dt, dt)
for i in range(1, len(t)):
y_next = y[-1] + dt * (-k * y[-1] + g(t[i]))
y.append(y_next)
return t, y
# Initial concentration of caffeine in the blood (mg/L)
y0 = 0
# Solve the differential equation
t, y = forward_euler(y0, g)
# Plot the concentration of caffeine in the blood and intake function g(t)
plt.figure(figsize=(10, 6))
plt.plot(t, y, label='Caffeine Concentration (mg/L)', color='blue')
plt.plot(t, [g(ti) for ti in t], label='Intake Rate (mg/L/hr)', linestyle='--', color='red')
plt.xlabel('Time (seconds)')
plt.ylabel('Concentration (mg/L)')
plt.title('Concentration of Caffeine in Blood over 24 Hours')
plt.legend()
plt.grid(True)
plt.show()
the grah is wonky now
Now it's fine
It's supposed to be like that yea
Your time scale was all squeezed out in your first graphs
oh cool
ah okay
so I'm done
?
Yea
yay
At least for that question...
this is why I don't like coding
Yeah the increase in concentration has units of mg/L/hr in the exercise
But now your time is in seconds for g(t)
So in 1 second you increase 3600 times less
So all your 40's should be 40/3600's now
Numerical computing in a nutshell
You fuck up a sign, everything goes wrong
reasons why I'm switching to mechanical engineering lmao
less cs stuff
import numpy as np
import matplotlib.pyplot as plt
# Define constants
dt = 1 # Step size in seconds
t_half = 4 * 3600 # Half-life of caffeine in seconds
k = np.log(2) / t_half # Decay rate constant
# Define function g(t)
def g(t):
if 0 < t <= 6 * 3600:
return 0
elif 6 * 3600 <= t < 6.5 * 3600:
return 40 / 3600 # Adjusted for unit conversion
elif 6.5 * 3600 <= t < 8 * 3600:
return 0
elif 8 * 3600 <= t < 8.5 * 3600:
return 40 / 3600 # Adjusted for unit conversion
elif 8.5 * 3600 <= t < 13 * 3600:
return 0
elif 13 * 3600 <= t < 13.5 * 3600:
return 40 / 3600 # Adjusted for unit conversion
elif 13.5 * 3600 <= t <= 24 * 3600:
return 0
else:
return 0
# Define Forward Euler Method to solve the differential equation
def forward_euler(y0, g):
y = [y0]
t = np.arange(0, 24 * 3600 + dt, dt)
for i in range(1, len(t)):
y_next = y[-1] + dt * (-k * y[-1] + g(t[i]))
y.append(y_next)
return t, y
# Initial concentration of caffeine in the blood (mg/L)
y0 = 0
# Solve the differential equation
t, y = forward_euler(y0, g)
# Plot the concentration of caffeine in the blood and intake function g(t)
plt.figure(figsize=(10, 6))
plt.plot(t, y, label='Caffeine Concentration (mg/L)', color='blue')
plt.plot(t, [g(ti) for ti in t], label='Intake Rate (mg/L/hr)', linestyle='--', color='red')
plt.xlabel('Time (seconds)')
plt.ylabel('Concentration (mg/L)')
plt.title('Concentration of Caffeine in Blood over 24 Hours')
plt.legend()
plt.grid(True)
plt.show()
Ayyy
I got it? Did I win?
Now our guy is not dead with 120 grams of caffeine in his body
Aight now that I'm done with that I can move onto stats. Yay 🙄
thanks for all the help
Gl with mech eng
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I wouldn't be too surprised if it didnt have nice algebraic solution
I feel like it has a easy solution but im not seeing it
<@&286206848099549185>
you plug in integers until you find one that works
genuinely the fastest way to do this problem
It seems like youtube problems that says "HARD OLYMPIAD PROBLEM" on title
yea but i have to algebricly
you are required to have an algebraic solution?
yea
This is solution to these kind of problems, but if you want real solution like some very complicated algebraic solution, I think you could use simple approaches or functions that are defined on N+
It's not easy though, that's why it's funny.
What exactly are you going to learn from this problem, have you ever solved this kind of problem before "algebraically"?
And problem must say what kind of number is x, it can be complex number, that would be weird with 1 base
@shy field Has your question been resolved?
yea but this one is hard as far
well x is 3
but idk how to deduce it
What's the difference between others and this one
mostly bec i cant simplify it or use ln or log
even if i simplify it it gets even more complicated
You said you want an algebraic solution, you should act like you don't know x yet.
exactly
There might be more solutions
@shy field Has your question been resolved?
<@&286206848099549185>
@shy field Has your question been resolved?
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I have learnt that $R[S]$ being the closure of a relation $R$ over $S$, can be computed inductively via $Y_0 = S$, $Y_{n+1} = Y_n \cup R(Y_n)$
Aresiel
I'm now trying to figure out how to compute the transitive closure of some relation $Q$ by assembling a relation $R$ and initial set $S$, and then using the above method.
Aresiel
I've figured out that $R = {((x_1, y_1), (x_2, y_2)) : x_1\in A, y_1 \in A, ... Q ... }$ where $A = (\operatorname{range} Q) \cup (\operatorname{domain} Q)$
Aresiel
But I can't figure how I further must specify R such that it generates the transitive closure
<@&286206848099549185>
@crisp anchor Has your question been resolved?
@crisp anchor Has your question been resolved?
@crisp anchor Has your question been resolved?
I believe I need to find a relation R which is equivalent with composition with Q
It is such that R[Q] = Q o Q
@crisp anchor Has your question been resolved?
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Trying to solve B but stuck at the red part
you are told P(3) = 18
Yeah
so set that equal to 18
Wdym..
wait, why do you have +18 on your P(3)
I threw the 18 in here
you were not
P(3) is the result of plugging 3 into the function ONLY
plugging x=3 in gets you
P(3) = 27 - 9r + 9 + r^2 = r^2 - 9r + 36
and you are told the numerical value of this is 18
yes
first isolate 2^n
So restart?
no
from what you currently have
isolate 2^n
and it should be clear what the value of n should be
why does it look like there's still a - sign next to the 16
and it should be clear what the value of n should be
I’m not seeing it
do you know your powers of 2
Ohhhh
It’s 2 to the power of 4
Thanks
@winter patrol is everything still ok here
Or did it go wrong
Ok so it should be a^2
yes
What if the quadratic isn’t factorable
quadratic formula
@restive river Has your question been resolved?
@restive river Has your question been resolved?
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@trail eagle
I know it yeah
But our teacher said that we should turn what we have into a series bcz using limit would be challenging
That's rather odd, I don't think you really need a series here.
See, we want gamma to be finite, and the denominator goes to 0. The only way this can happen is if the numerator goes to 0 as well, right? Otherwise, the limit would be c / 0 and that just blows up.
So if you plug in 0 (the value we're approaching) in the numerator, and try to set = to 0, what does that tell you?
im actually curious what series your teacher is thinking about to solve this because i dont see anything
1+BETA-0=0
BETA=-1?
Not far, e^0 is 1, alpha stays there and (beta + 1)*0 = 0
I am not sure about this question but we solved something similar to it
I meant alpha sorry not beta
Yeah
Now try and use L'Hopital's rule and apply the same idea.
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Hi
Good Job!
@halcyon yew Has your question been resolved?
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for f(x)=3x 1 and g(x)=x^2-6, find the (f-g)(x)
can someone explain how to solve for this?
$(f-g)(x) = f(x) - g(x)$
ℝαμΩℕωⅤ
so
(3x+1)-(x^2-6)
is the answer x^2+3x-5
is there any part of my answer that was right?
Only +3x lol
yes
if its asking to fine the (f+g)(x) will it be (f+g)(x)= f(x) + g(x)
yes
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Why is the rank nullity theorem formulated in terms of columns in particular
Please don't occupy multiple help channels.
closed
and not rows?
columns correspond to the dimension of the domain for the matrix
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Stats and Prob, Estimating a Population Mean
need to know how to do the Za/2 caculation on my ti-84 caculator
LOL start your own help channel
is it from area under distribution curve to z-score?
nah I remember now
looked through my notes
InvNorm caculator function
but thanks for willing to help
you may wanna help that newbie
was about to say that but all g
.close
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Trying to solve question c, factoring by grouping, not sure what I'm doing wrong or what to do to after that part
I'm pretty sure I was already doing x is cos(5 pi t/3)
I don't think I'm supposed to use rational root theorem, I don't think we've learnt that
Teacher says factor by grouping then solve resulting trigonometric equation for t
I'm stuck at not being able to factor because the -8 and +17 don't match
<@&286206848099549185>
that cant be factored
wait um it tells you that d^2=9
so you can must put the 9 to the other side
so the 17 becomes 8 and then you can factor it
and also yeah let x=co(5/3pit) to make it visibly easier to factor
did you get it or do you need more help?
Ok, makes sense
Not quite sure what swaps with the 9 tho
Will probably get suck again later
wdym
what swaps with the 9?
9 moves across the = , does it become 0?
the question tells you that d=3 so d^2=9
so you have 9= -16cos^3.......+17
you move the 9 to the other side and you get:
-16cos^3......+8=0
and you factor it and solve it
Yeah, so 9 = .... becomes 0 = ....
Was just checking that
well yeah, you basically subtract 9 from both sides
Ok, I'll be alright for a little while now
Thanks
alr ping me if you need more help
In dm?
wherever you want , dm as well
That'd be awesome, thanks so much
np
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help
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can someone please check these for me
for 25 I got x=pi/2 +- pi(n) , x=0 +- pi(n) , x = 7pi/6 +- 2pi(n) , x= 11pi/5 +- 2pi(n)
<@&286206848099549185>
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show your work
$x=0, x=-\frac{\pi}{6},x=-\frac{7\pi}{6}$, and $+2k \pi$ for each one
democracy_landing
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So for the last table they have given a formula for probability X>
1/y (which is basically probability of X>x as 1/y=x) so for the value of x = 2 we need to find P(X>2) which is equal to 1 - P(X<2) and P(X<2) = F(2) and we can see from the second table (on page 178 the left one) F(2) is 5/8
1- 5/8 should be 3/8
Like I don't get that
Please explain
@worldly sonnet Has your question been resolved?
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@worldly sonnet Has your question been resolved?
@worldly sonnet Has your question been resolved?
@worldly sonnet Has your question been resolved?
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Show that (p ∨ q) ∧ (¬p ∨ r) → (q ∨ r) is a tautology, by using equivalence laws.
can someone help me with this because i dont know how to do it
do u know what tautology means?
to prove it is True
that's not a tautology
it means a true statement
ok
well if its F then its vacuously true
so u just need to prove that when its true the right side can only be true
If its F then it is a contradiction
no
ye distribute that
like make (p ∨ q) ∧ (¬p ∨ r) into a single statement
get rid of the and
in the middle
using equivalence laws?
ye
¬(pVq)->¬(¬pVr)?
tilde is not
I get q v rp
-> q v r
what law did u use
ye
ummm
use distributive
(p ∨ q) ∧ (¬p ∨ r) the second p has negation
in the distributive law there is no negation
ok but its irrespective of the sign
like(p ∨ q) ∧ (¬p)
what is this
and then (p ∨ q) ∧ (r)
what is this
and then
(p ∨ q) ∧ (r) v (p ∨ q) ∧ (¬p)
what is this
are u able to send a photo of ur working?
so it doesnt matter if it has negation or not
i havent worked on it because im trying to understand how to do it
start here (p ∨ q) ∧ (r) v (p ∨ q) ∧ (¬p)
and try to use equivalence laws along the way
see what u can cancel
just one question
ye
if the equivalence law doesnt have negations but i have can i still use it?
yep
yep
that is equivalent to p
i get q v pr
well this says p v (q and r)
can u send ur work?
well i havent done any work
just based on the laws
that is what you get
(p ∨ q) ∧ (¬p ∨ r) is equivalent to p v ( q and r) based ondistributive law
no
why
no
then ur using it wrong
please first tell me how to distribute (x + y)* (z+w)
let x, y, z and w be just random variables
and + is normal addition and * is normal multiplication
u can think of v as + and * as and
its similar enough for this question
wait
x times z + x times w + y times z + y times w
that would be
p and ¬p V p and r V q and ¬p V q and r
its a lil off
why
u only had 4 terms here
but u have 5 terms here
should be same number of terms
also also v is or and ^ is and
no cuz for the xy thing, u get xz + zx + wy + yw
but for the thing above u get
nvm I'm just stupid
I'm sorry
ye that's right
super sorry
miss read
no problem
but there is no law that i can do with this
@severe orchid
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Alright, so, another question. Ive simplified an inequality down to this and know the vertical asymptotes are 3 and 0.778, and I also no there are no x intercepts. But I have a very spotty idea on where exactly to go from here. I cant really find a good explanation of how to make an interval table which I need to do to get the answer, nor do I really know what to do without the x intercept, which Im pretty sure I need to make that table. Any help would be appreciated!
what answer are u looking for exactly
Pretty much how to build an interval table from this
and maybe how to build one in general
Best way to do interval tables is to create tables at each root of the denominator AND the numerator, and then in the table just note for each interval whether the num and denom are positive or negative so whether teh overall fraction is
imagine this but with the points being all the roots of the numerator and denominator, and then the signs of the numerator or denominator
then just check the sign of the numerator thats why I said the sign thing
if theres no root the sign should not change across the table!
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PQ is a tangent at Q and PS//QR. Prove that angle SPQ= angle QSR.
wasnt given a graph
@pseudo rain Has your question been resolved?
@pseudo rain Has your question been resolved?
SPQ is not equa to QSR if its's just random points
Are you sure it's no SPQ = PQR?
Or smth similar, cuz randomly placing the points isnt always gonna give the same result
im not sure
Also "tangent" to what??
i think the question is too vague
i wasnt given a graph so i dont know where to start
Well where'd you get this alleged question
tutor
Well like that it makes little to no sense i think, maybe you missed a part?
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Relating to question 1, how do I find delta x?
the spaced apart number, 1.5
Dont want to be clog the learning but maybe in a general channel can you tell me how the special roles are earned?
But it says the in answer, delta x is 3
@spare crypt
oh huh, seems like it's a midpoint rule thing
like you're only allowed to use the data in the middle of rectangles
Wdym?

