#precalculus
1 messages · Page 19 of 1
is the map of a vector b which underwent a transformation by an nxn matrix equal to the vector v given by the vector b multiplied by the matrix?
also i understand what these means in terms of functions but what does it mean with matrices
😂
some people man
<@&286206848099549185>
Someone explain to me what the hell the prime notation (') symbolises please
I am braindead
Depends on the context
Usually when u see f'(x) it means the derivative of f(x)
Usually y' is also a derivative of y
Why does f(x) have negative zeroes? Isn't its leading coefficient x^4, an even number meaning it should have only positive zeroes?
Isn't its leading coefficient x^4, an even number meaning it should have only positive zeroes
not sure why you would think that would ever be true
I mean x^4 goes like this
x^4 - 1 has negative zero
You may be interested in (or misremembering) https://en.wikipedia.org/wiki/Descartes'_rule_of_signs
That doesn't seem to belong in precalculus.
j'
explain slope intercept
do you know the way of graphing a slope?
Courses on Khan Academy are always 100% free. Start practicing—and saving your progress—now: https://www.khanacademy.org/math/algebra/x2f8bb11595b61c86:forms-of-linear-equations/x2f8bb11595b61c86:intro-to-slope-intercept-form/v/slope-intercept-form
Slope-intercept form
Practice this lesson yourself on KhanAcademy.org right now:
https://www.kh...
this might be useful
also i think this is the wrong channel for this
Y = mx+b? Can't remember, our teacher isn't using books
yes mx + b
but that khan academy video would help you alot
<@&268886789983436800>
if you want i can explain it to you, there is no problem
Sure I don't have a problem on hand atm but I don't mind
After I find the y intercept the rest is like thin air to me, also our instructor switches the numbers around without showing their work so it's irritating
alright
when two slopes intercept, their x and y is equal
for example, im asking you to find the intercepts of x+2=y and -x+4=y
x+2=y (2,0) (0,2) and -x+4=y (4,0) (0,4)
Guys I need help with one question
I have it partially completed
it's very likely that the last part of the question is wrong
what are you supposed to do
end behavior? forgot what that was
but ur doing logarithms right?
Idk what that is.
If you ask an actual question, there's a chance that someone will answer it for free!
Does noone here know how to do this?
quadratic formula
That from a test?
y= b^2+-squrt -b+4ac over 2a.
no
100^2 +- squrt -100+4(4.9)(318) over 2(4.9) =y
thank u my king
A is 23 seconds. B:828.204 peak
don't know if thats what you are looking for.
that's what I got
use the -b/2a equation, whatever you get from that plug it in the equation and that gives you the answer for num 3
q.3
no one answered my question 
is it exponential stuff?
I don't know that.
looks like it
adding functions and determining the end Behavior's.
do you have any previous work
that is the same as that question
so we can kinda guide ourselves
lol
not really.
so is this the first time you are seeing this?
damn like I need some material else I won't be able to help u
Yeah.
Like I have tryed to look stuff up so I could figure it out on my own and can't find anything.
have you asked chatgpt
u know how to do this one
yes
i think it's x^{2}-5x+2
check on desmos
oh you changed pics
lol
my bad
lowkey forgot but I just know that y is 1 and that it opens down
vertex is -3,1
I can't remember correctly, sorry
I have now.
Think It gave me the right answer.
ty
👍
long division
synthethic there might work but use long division
lmk what you get
I still don't get this:
ok I think i get it now
I would like to hook you guys up with some free courses, Check 1T 0u7!!:
https://alison.com/course/clep-pre-calculus-trigonometry?utm_source=alison_user&utm_medium=affiliates&utm_campaign=33806002
anybody know the inverse function formula?
im trying to solve $x=y^2+y$ and get y alone
x927373
this is quadratic equation in y
there will be two inverrses though
Can I have a rectangle where the domain of the length of one side is [0, p/2] where P is the perimeter?
In this case the rect will have two sides and both of them will collapse to be on the line
Is this valid? This is mentioned in the solution to one of the questions in the book I am reading
What is the intercept point? I mean (x, y) [they intercept at one point]
Just tell me what are the answers for x and y. Let's not talk about intercepts for now
x+2=y
-x+4=y
Don’t you just have to switch Y with X?
I think that’s how it goes and then just solve for x
I tried by taking (dz/dy)^2 common from rha, but idk
is that derivates
how to draw the graph of x^6(1-x)^7
if you remember, we could find "x" in a quadratic equation and we say x=(-b +or- sqrt(b^2 -4ac))/2
basically you only have to do the equation for y and find out y= your answer
but im not quite sure if that function can be inversed, because there are two "y"s for one x.
but if you want to get the y alone, you just have to put it in the quadratic equation and solve it
People here seem to type whatever random things to these channels
Partial derivatives? Seems pre-calculus to me!
Yo
this is the prompt for my assignment "Sketch the graph of each function by transforming the graph of an appropriate function of the form
y = xn
from the graphs below."
Just wanted to know if there was a quick vid that explained how it all worked
i think it might be -1, 1, 2
im not sure if 4 would be one of the actual zeros since you dont see it hit the x axis on the graph
^^
there can not be an odd number of rational zeros
leading thing is four
so there has to be four zeros
and imaginary zeros come in pairs
maybe they wnat you to put -1 twice
ohh yeah, theres a double root at -1 which is why it turns (triple would be inflection , and 1 root would just pass, like at 1 and 2) lol sorry i forgot
Help
it's because there's a double root at -1, which visually just means theres a turning point there
oooo nice thank you
I’m stuck on part b here, I got the right answer for a by finding each volume individually and finding the difference but im not getting the right answer for b
is anyone there ?
no one
any help with this please🙏
how is this possible
log can nver be equal to 0 as per its range and here they have equlity with 0
@digital mirage output of log function can be 0
ohhhh
right
tahts is exponential lmaooo
@warm oyster but still cos(sinx) must not hold equlity with 1
there's no such point where cos(sin(x)) > 1
yes but im saying here as it is written as >= 1 is not possible by log properties
cos(sin(x)) > a^y is what property say
ya but what about this property ?
what property
how these 2 can be true at same time ?
but my Q is stasfying those suitable values
one is true for a > 1, the other is for a between 0 and 1
it only satisfies one of them
3 > 1, but not 0 < 3 < 1
can logarithmic spirals pass theta=2pi? my calculator stops there
can someone help explain what this means 🥲
solve the equation sin(x) = -sqrt(3)/2
are you good with functions and stuff
like I need help like 12 hours from now if your active because I left my HW at school and only have like 30 mins to finish it
I won't be here by that time
hm ok
its asking for specific x values tho
can you solve the equation sin(x) = -sqrt(3)/2 though
hbu?
i got like half the answer right but its asking for 4 values idk
thats where im confused-
well I need to know what you're doing
nvm nvmmm i got ittttttttttt
i apprecate the help anyways :)
For future reference just graph that stuff
Or memorize the key points and know how to apply that into a given equation (in this case it would be pretty simple)
It’s generally easy when dealing with sin/cos
ln(a) + ln(b) = ln(ab)
here sin(1/x) can give values from -1 to 1 . now if it gave the value 0 then it will lead to 0/infinty and further leading to 0/0 .... then how to solve it ?
saddayyy_
u = 1/x
x->inf, u->0
lim_{u->0} u sin u
= 0?
do u guys think i could like self study over thanksgiving break
to be ahead / used to precalc or will it be like 2 hard to do
Anyone know any good videos on logarithmics, its something I just cannot fully wrap my head around no matter how hard I try
View full lesson: http://ed.ted.com/lessons/steve-kelly-logarithms-explained
What are logarithms and why are they useful? Get the basics on these critical mathematical functions -- and discover why smart use of logarithms can determine whether your eyes turn red at the swimming pool this summer.
Lesson by Steve Kelly, animation by TED-Ed.
<@&268886789983436800>
how do u turn a negative exponent fraction positive again.. 
Hey guys, been stuck on this for 10 minutes, how do you solve this?
You have concluded that, log(x^2/7x-1)=0.
10^0=1
Any number to the power of zero equal one
No problem
So, it's gonna be 1 = (x²/7x-1) right?
Why do I feel like I'm goin to use the quadratic equation
Ah alright, good night!
i think for a im supposed to plug in x=1 through x= 12 in to graph the equation but lmk if im not doing this right
but i need assistance with this problem
If you are allowed to then just use a graphing calculator for this
Then looking at that would give you the answers to b and c
Just plugging a few numbers in won’t account for any irregularities
Which could affect answers to b and c
The qst asks us to find the function for this graph
I know this function is 1/x. But it is flipped so that makes it -1/x.
And there is a VA at x= -1 so that means the function is -1/(x+1)
The part i am confused about is how in the world is the x intercept 2 and the y intercept -2? I plugged the -1/(x+1) into desmos but it gave me this
Am i missing something? Does it have to do with the hole?
Does anyone have anki cards for mathematics
Did u get the answer
Oo i remember seeing these but never knew the name ty, pls let me know if you find any
Ummm so how can I understand trigonometric identities
Yes.
Derive them
hi i was wondering if someone can help me with a question
i need to find the coordinates for a point (x,y,f(x,y)) but all i got is the function f(x,y)=y^2+2xy and the tangentplane z=6x+4y-11 in the point (x,y,f(x,y))
What was it
I have an exam tomorrow in calculus
hello my guys
I'm trying to get help in the channel, but maybe I can ask here
I want to know if a table of values is correct or not. A teacher presented me with a table of (x,y) values that looks like this: (0,1) (1,4) (2,10)(3,20)(4,35). This to me appears immediately to be a tetrahedral function/sum of triangular numbers. y=1/6x(x+1)(x+2). Simple. However, of course, a true tetrahedral would have a slightly transposed table of values: (0,0)(1,1)(2,4)(3,10)(5,20)(6,35) etc. So what's up? Did the teacher just mistype the list of values or do I need to figure out a different function?
divide both sides by the value such that the right side will be 1
what's currently the right side of the equation?
thus what should you divide by?
but how about the left side
you divide both sides by that same value
then do some additional manipulation if needed
the first goal is the get 1 on the right side
do what i mentioned and tell me what you get
how are you getting 9 in the denominator
36/4
isn't 1/9
oh yeahh
also missing the () and ^2 for the y-8
i divided it by 1/4
you shouldn't be doing that
always remember, same operations to both sides of the equation
divide both sides by 4
or multiply both sides by 1/4
or equivalent
well i divided it by 1/4 as fraction rules so i got 4x2 and (x-8)^2 x1
thats how i got it
that's not division by 1/4
that's multiplication by 1/4
and regardless that won't give you 9 in the denominator
division by 4 is multiplication by 1/4
no its for the left one'
?
since its also a fraction
you might be doing some valid math for some parts but aren't properlly describing what you're doing
yeahh EHAEHAEHAE
wait ill show my work and please judge it
here
dont mind my handwriting 😛
ℝαμΩℕωⅤ
ohh
don't overthink what its supposed to be
its 4/36
no
wat
aint it just 4/36
no
and simplified 1/9
$\frac{36}{4} \redneq \frac{4}{36}$
ℝαμΩℕωⅤ
yeah thats why i said 4/36
and that's why its wrong
4 as nominator
which is wrong
forget about the elipse equation / the final desired form
this is a simple question about division
alright im joking i know its 36/4
what is 36 divided by 4
how many times does 4 go into 36
gosh lel
i can't tell if you're joking
1/9 and 9 😛
those two questions were asking the exact same thing
😛
yes, 4/36 is 1/9,
but you don't have that here
36/4 is simply 9
dividing both sides by 4, you should have
$$\frac{(y-8)^2}{8} + \blue{9(x+1)^2} = 1$$
and to explicitly express the $\blue{9(x+1)^2}$ in the form $\frac{(x+1)^2}{\red{k}}$ you can apply the reciprocal relation between multiplication and division. \
$$\frac pq = \frac{1}{q/p}$$
$$9 = \frac{1}{1/9}$$
thus
$$9(x+1)^2 = \frac{(x+1)^2}{\red{1/9}}$$
ℝαμΩℕωⅤ
im sorry for all this trouble and its just because i forgot basic math 
thank you for helping mee
Tymsss
everything divided by infinity is 0
for me 3ln(ab)
i got z=7, y=8 and x=-6
Yeah I got it
but its 0/0
how does 0/inf lead to 0/0
i mean just u =1/x ?
Pre calc is everything you need before Calculus, Algebra 2 if I remember has functions more in debt alongside polynomials complex numbers and a few fun stuff. But you won't see any geometry (please update if I'm wrong) in Alg2.
what
the value of sin 1/x approaches 0 and denominator goes to infinity so it should be 0
0/inf = 0
what do I start now?
do a few lessons and see what you feel comfortable with doing :)
well I want to go to calculus cuz my old math teacher said you don't really need precalculus but I don't want to skip anything to important
i would say precalc is very important to calculus
but that just depends on how much precalc you already know
i.e. trig, logs, exponentials, etc
I did alj 2 so yea I know all those things
if x+1=4, then what is 2x+2? Im really struggling with this question.
well theres two ways to go about this
- u can solve for x
- u can multiply both sides by 2 for the first equation and get ur answer directly
hi guys, can anyone check my solution for this problem pls. tysm!
https://discord.com/channels/268882317391429632/1170661519655178301
like trick to memorise them?
like what identity should I iuse for this problem
for example
Tan theta can both equal to
sin0/cos0 or tan0 = 1/cot0
Most of those I'd derive as necessary by writing everything in terms of sin and cos.
pretty strange sometimes i just dont get notified about the pings
but for instance, sin is = 1/csc. when do I use these types of identities
or do i js literally disregard everything there and just write everything to sin and cos
As far as I'm concerned, csc(x) is defined as a shorter (and less enlightening) way to write 1/sin(x), so the identity is trivial.
so if i had to prove a problem with 1/csc in it, I js rewritr to 1/sin?
No, if it says 1/csc(x), that means 1/(1/sin(x)) which is the same as sin(x).
(Unless the lhs is not defined due to division by zero).
oh yeah mb. wdym by division by 0 btw?
1/csc(0) is not defined, whereas sin(0) is.
what's with these ridiculous exercises like "express log6(16) using log12(27)"? i don't see any kind of pattern for solving them, you just have to guess the right order of steps that might lead you to the answer?
Hmm, you could start by expressing the two values as $\frac{4\log2}{\log2+\log3}$ and $\frac{3\log 3}{2\log2 + \log3}$ ... but that doesn't really seem to point to any nice relation between them in this case.
Troposphere
But you can reduce the number of "unknowns" by declaring that the logarithms in those fractions happen to have base 3, and then you're looking at expressing $\frac{4x}{x+1}$ in terms of $\frac{3}{2x+1}$ which is a matter of (slightly messy but) straightforward algebra.
Troposphere
hmm our teacher hasn't used unknowns in any of these exercises so far
this is the solution in my textbook, under 3)
looking at these solutions, I have no idea how I was supposed to think of that... each exercise has its own incredibly specific trick
That looks like it's basically the same computation I suggested, but more confusingly written by writing log3(2) all the way through, where I decided to name it x to make it more unobtrusive.
The solution in your screenshot is just the final proof, with no easily visible trace of how it was found.
My reasoning might have been a bit brief, but at least the first step in it was pretty systematic: express everything in terms of logarithms of primes.
The trick of choosing one of those primes to be the base of all the logarithms probably is something you only gain from experience.
But after that the only logarithm left was log3(2), which allowed me to use elementary algebra to relate the fractions.
If you haven't even seen algebra, it feels like asking you to come up with such rewritings on your own sounds like a rather big task.
thank you, I'll try to apply this in the future
,rccw
the range of the sin(x) functions is [-1,1] not [0,1]
??
fx under cos must be from -1 to 1 ... that what i did
wdym fx?
I can clearly see you wrote [0, 1/e] tho
sorry its y , by mistake i wrote x
depends on the questions
Hello
How do I read the graph to get the domain n range?
it wasnt tauight from what i remember in class he just guestimated the lines
recall the definition of domain and range
domain is x axis range is y axis
Hi everyone, does anyone know of a location where I can obtain quality exercise with challenging problems and corrections? *
What level of math?
,, 1=\cos^2 \theta + \sin^2 \theta
🐱!Yajat! 【Catfan1398】🐱
,, 1^2-sin^2 \theta = (1-\sin \theta)(1 + \sin \theta)
🐱!Yajat! 【Catfan1398】🐱
oh is it bc 1^2 is 1? im so stupid sry
yes for 1^2 is 1
in other words, if f(-x)=f(x), it's symmetric over y-axis, if -f(x)=f(x), it's symmetric over x-axis. The only one not explicitly identified here is symmetric about origin, which means a function is odd which means f(-x)=-f(x)
so just tests these and you should be good :)
@untold python
Ohhhhhh!!! Thank you sooo much!!! @novel creek
Hey does anyone have some good videos to watch for reverse chain rule and integration by substitution?
thanks
you need trig
thats what im slaving away at rn
some people study trig in alg 2
Idk how many people are in Canada
However you would it be realistic to study all of Precalc in 3 months over the course of the summer as with also advance functions?
Would it be good enough preparation of getting a solid 90 or 85?
With also adage of studying more advance stuff on the side as per calc?
How do I solve this?
g is the inverse of f, since g(f(x)) = x
or equivalently, f is the inverse of g
Is it correct?
yes
no worries
recall the definitions of odd and even functions:
odd -> f(-x) = -f(x)
even -> f(-x) = f(x)
try substituting x = 1 etc into those definitions
(you can think of these functions graphically: even functions have left-right symmetry, and odd functions have symmetry across quadrants 1 and 3; 2 and 4)
Wdym can you please elaborate?
like for the first one, (1, 2) is the reflection of (-1, 2)
and (4, 7) is the reflection of (-4, 7)
so it works out
that function is even
Okay
Then for the second option?
It is odd
Cause -x,-y exists?
@willow skiff
yep C is correct
in fact, if you substitute x = 0 into f(-x) = -f(x)
you get f(0) = -f(0)
or that f(0) = 0
in other words, every odd function must pass through the origin
Didn't get it please elaborate
f(-x) = -f(x) is the definition of an odd function
and if f(0) = 0, that means when x = 0, y = 0
that point is precisely the origin
like if x = -x, adding x to both sides gives you 2x = 0
or x = 0
<@&268886789983436800> uh spam ig?
If an odd function is defined at x=0, then that automatically means the output of the function at x=0 must be 0 in order to maintain odd symmetry
In other words, if an odd function is defined at x=0, it must pass through the origin
hey so i feel like I have a solid basis of algebra and trigonmetry but I really don't know how to tackle calculas. Its something that I have heard about and would love to learn about but I don't know where to begin
u need to be rlly good at algebra and decent at trig to begin
you mean like trig funtions unit circle and solving triangle's cuz I did those in alj 2 and geomatry
hi can someone help me find this limit
i know the answer might be something easy cuz log base 7 of 0 does not exist, but i also got that x > 0 so it might range in the positives?!
I'm pretty sure that the 140 at the end gets the exponent as well
It approaches 0, but is greater than 0 implies that it's 0+, because 0+ > 0. Since it never becomes 0, it will approach a value. When looking at the graph of log7(x), there is an asymptote at x=0. Since x approaches 0+, it would be reasonable to assume that the function approaches infinity
it approaches +inf or -inf?
k ty
You're welcome
I guess but is there any place online where I can learn it. Currently I am watching 3 brown 1 blue's video but thats about it
how to turn this into logarithmic?
can anyone explain calcules to me please ?
what do you want to know
calculus is a pretty wide field
can you explain the bare basic in bare basic terms
yeah
so, in simplest terms, calculus is two main operations
differentiating and integrating, and they're opposites
i can't easily explain what they do but they're both based on the concept of a limit
which is a value a certain function approaches (but this doesnt necessarily mean it'll reach it, it's just what it approaches)
so if you have a function like this and you're trying to take the limit as x approaches zero from the right, you're going to get a value of zero
but if you take the limit as x approaches zero from the left, you're going to get a value of three
and thats the bare minimum i can explain easily
the notation looks smth like this
where right and left are noted by plus or minus signs next to the a
How?
so the first step here is gonna be taking the 4x our front and making it an exponent right
so the 4x can become an exponent of the 7 because we're working with logs right
yeah that works too
I just don't get the step where (4x+1)In 7
i mean if it doesnt i dont see errors there
the step where you move the exponent to the front? or the one where you distribute
the one where you distribute the 4x+1
yeah so as far as i know that just works like any other multiplication problem
it looks like you did it right from what I can tell
This from video I was watching
OHHH okay
I don't get how (4+1)in7 = 4x*in7+in7
yeah so basically. all we're doing in that step is multiplying 4x by ln 7 and then multiplying ln 7 by 1
its the natural log so we treat it like any other number or variable
when we multiply like that
so like. if you have smth like this
okay
O I get so he didnt multiple the Nartual log of 7 with 4x because the number dont share the same variable so he left as 4*in7
I have an equation ax^2+bx+c=0. What are the conditions on b and c such that the solutions are
- real and positive
- real and negativ
if a<0
you need to use the discriminant
the discriminant is sqrt(b^2 - 4ac)
you may see it in the quadratic equation, if the result of the discriminant is positive and larger than 0, than the roots are positive and real. If the discriminant is positive and less than 0, than the roots are negative and real. And if the discriminant is negative the roots have complex feelings and want to be special.
(x^2)+3x+9
(-3(plusminus) root[9-36])/2
(-3(plusminus) root[-27])/2
(-3(plusminus) 3root[-3])/2
(-3(plusminus) 3iroot[3])/2
1.5(plusminus) 1.5iroot[3]
1.5+1.5iroot[3], 1.5-1.5iroot[3]
I have an exam coming up and I was wondering if anyone would help me study
What are the topics?
Systems of equations, exponential and logarithmic functions, finding domain of functions
What are you having difficulties with? (if you are having difficulties that is)
Mostly expanding logarithms and giving the exact solutions to them.
I’ll show what my exam says so you understand what I mean by giving exact solutions.
Are you doing everything in base 10 (log_10(x) or log(x))? or are you doing logs of different bases?
How familiar with your logarithm rules are you?
Not very familiar
Here’s another example of what I need help understanding
I’ll save this
Okay lets start with q6a) ln(x^3 * y)
Ok
We can apply the law of products which stats that log(ab) = log(a)+log(b)
so we will have ln(x^3)+ln(y) //then we can apply the law of exponents which is log(a^b) = blog(a)
that means the final solution is 3ln(x)+ln(y)
Ok I follow
I will go over the second question as its a bit more complex, then have a go at the final question.
Ok
log( (sqrt(x)*k^2)/(m+1) )
Start by applying the law of ratios
log(sqrt(x)*k^2) - log(m+1)
actually, i think thats it
Oh I don’t need to do anything further?
I don't think so, I though it said sqrt(xk^2), but because it just says sqrt(x)*k^2 we dont have to go any further
Ok makes sense
But if you have to, like in the final question, recall that a square root can be expressed as a fractional exponent
I don’t think I have to do that
for the final question you have to change the inside of the logarithm from the fourth root to the power of 1/4, then use the law of exponents to move it to the front of the logarithm.
Oh ok how do I do that?
Look at the inside, it is
you can change that to be (ab^3/c^2)^(1/4)
then you can use the law of exponents to move the 1/4th to the front of the log
Oh I see. Does that get rid of the square root?
So it would be written as 1/4 log ab^3/c^2
yes
Do I use the law of ratios after that?
yes
Ok I think I’m starting to get it
The last question is a bit complex
Yes it is
Tell me once you think you have gotten the answer
Ok
okay, what did you get?
3 (1/4) log3 ab - 2(1/4) log3 c
okay, this is pretty much the answer, and you would probably get full marks, but you can move 1/4th to the front of some brackets to make it look cleaner
also you cant take the 3 out
Oh I thought I could
because log_3(ab^3) isnt log_3(ab)^3
its tricky, but if you are able to tell the difference between ab^2 and (ab)^2 it shouldnt be much of an issue
i sometimes mess up like that as well, so dont worry
Right. I’ll make a note of that
do you know how to do question 12a in the original work sheet you posted?
No
Yep
so for these types of questions you need to make everything have the same base number
so 2^(4x+5)=8 would become 2^(4x+5)=2^3
Now, using the same base rule of exponents, if x^a=x^b, then a=b
so 4x+5 must be equal to 3
so you'll just have to solve the equation 4x+5=3. which gives you the answer x=-1/2
Oh right! That makes sense now
And to verify, plug in -1/2 into the original equation.
Right
Ok
Because both sides have different bases you cannot use that trick to solve for x.
Ok so does that mean we need to make the same base?
Nope! We can use logarithms! (yay)
Oh ok
We can take the log of both sides (doesnt matter the base of the log)
but because you are learning natural logarithms, i will be using ln(x), which just means log_e(x)
Ok
3^(x-4)=7^(2x+5)
ln(3^(x-4)) = ln(7^(2x+5))
(x-4)ln(3) = (2x+5)ln(7)
from here, it should be pretty easy to figure out, but if you havent already, i will continue
xln(3) - 4ln(3) = 2xln(7) + 5ln(7)
xln(3) - 2xln(7) = 5ln(7) + 4ln(3)
x( ln(3) - ln(49) ) = 5ln(7) + 4ln(3) factorise x
x= (5ln(7) + 4ln(3)) / ((ln(3)-ln(49))
@pulsar vessel and that is the exact value
I would probably write this down on a book or a notepad
okay, good job
if you need clarification i am more than happy to make a line easier to understand
a helpful tip you should try doing is writing down the law you are using next to the line you used one in.
Oh good idea
Or if you want to be more precise, write down what process you are using if you arent using a specific law, like when i took the common variable (x) out of the logs in the 6th line
Oh ok
Do you think you are starting to understand logarithms and exponents now?
Yes I think I’ve got it now
okay, try this question
You will need to use the law of exponents, law of ratios, law of products
btw alog(b^c) = log(b^ac)
I got logb(8m^12/3)
good job, you got the correct answer!
Awesome!
I think it’s finally starting to click. Now that I’m getting more familiar with all the rules
Now, the best way to keep improving from here (aka getting more consistant) is to just do a bunch of questions. Use the textbook your school gives out, or ask your teacher for more resources, and just start doing problems.
Ok I will do that. My textbook has a whole unit on this with practice questions
When I was learning logarithms initailly I think i did over 300 logarithm questions in 10 days (outside of school). But you don't have to do that many, just like 50 and you should understand them.
Wow that is a lot of practice 😂
It was only like 30-45 minutes a day
Ah fair enough
A lot of the questions when i started were stuff like log_2(256)=x
sometimes i type too fast for the math to math
Haha I get it
Anyways, you also said you were doing simultaneous solutions (systems of equations) on your exam?
Yes but I’ve got those down pretty good
Ahh, thats good. They will show up everywhere in algebra and calculus.
I’m starting to notice that lol
That’s why I decided to actually learn them this time around
yeah, good idea.
Anyways, thank you so much for helping me! Really means a lot
np
Can someone help me with my homework? I would really appreciate it .
What topics?
Analyzing graphs of functions
How much difficulty are you having with the topic?
A lot, I’ve had covid and I’ve missed the past two weeks of school and I’m really behind.
Okay, give a few examples of the questions you are having difficulties with.
Do you know what domain and range is?
Yes I know how to do that just everything else is confusing
Okay, so you don’t know what continuous and disconnected equations are?
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When solving a system of equations using matrices, how do you know if you have no solution or infinite solutions?
when you have an equation of the form 0 = 1 or 0 = 0
for the quadratic equation does A always have to be equal to one like for example problem 2x^2+3x-10
Oh ok
!da2a
No need to ask “Can I ask…?” or “Does anyone know about…?”—it’s faster for everyone if you just ask your question! See https://dontasktoask.com/
a can equal anything, but it can always be cancelled out. eg 2x^2+4x+6 can be x^2+2x+3
Find the sum of all values of $\theta$ such that $\theta\in[0,2\pi]$ and$$ \cos(\theta)+4\sec(\theta)=8 .$$
Mathboy123
To solve that question you must use trigonometric identities and general solutions.
The first step should be to fnd the angle, this can be done by multiplying both sides by $\cos(\theta)$, from there you can move everything to one side you will get the result: $\cos^2(\theta )-8\cos(\theta)+4=0$
TheLord26
From there, how I went about solving for $\theta$ was to let $\cos(\theta) = x$, and solve for x using the quadratic equation.
TheLord26
yes and i solve quadratic equation but i get weird radical
What do you mean?
(x=2\sqrt{3}+4\ x=-2\sqrt{3}+4)
That is correct.
so 8?
Then you will have $\cos(\theta)=x$, and from there you will find that $2\sqrt{3}+4$ does not have a possible solution, so when you use $-2\sqrt{3}+4$ you will find the value of $\theta$ to be 1.00522.
TheLord26
Finally use the general solution to find all values between 0 and 2pi.
And well, add them all together.
yes
if im given this and its telling me to expand
is it okay to write it like this
or would I have to distribute the 1/5 to each one
ex) 1/5 + 4/5 - 4/5
it's correct
<@&286206848099549185>
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I mentioned people for her question not mine lol
Well, don't.
💀
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Oh sorry I didn't see the message
💀
Ok I'm sorry what I'm suppose to say
Can the domain of a log be negative?
nah
Ok 👍
Yes
Because exponential can be negatives
If you allow stuff the be complex
quite famously, e^(iπ) = -1
why is this possible to do and why do you do this?
It's because the you are multiplying by 1, and in trigonometric proofs you can multiply by 1. The reason you do this is you hope to simplify the right side and turn it into the left side, what you should be looking at now is expanding the top of the fraction and manipulating it to be equal to cot(x)-csc(x)-1.
Hey guy's, i had a question, is algebra 2 enough to proceed into precalculus?
go ahead
why we dodnt write g(lambda+pi/2 ) ? lambda is also varibale here
and why lambda cannot be zero ...
Why quadratic functions graphs are always curved?
To solve this you must ask what the difference between linear functions and quadratic functions are
a linear function can be determined by y = x and a quadratic function by y = x²?
The difference between the graphs
It's the slope
The slope of a linear function is always constant whilst for a quadratic it changes
why?
Because x is squared — $2^2=4$ $3^2=9$ $4^2=16$ see how 4 changes to 9 which then changes to 16? It changes from +5 to +7 and so on
prime
Linear functions don't have that characteristic and change at a constant rate which is "m" in y=mx+b
I am getting to understand it, can I apply this logic for other type of functions like cubic or fraction ones?
By fraction do you mean $\frac{1}{x}?$
prime
And yes, yes you can
yes
I believe it's called Khan Academy
How do I insert this into a calculator? I can’t do the vertical line
if its a gaussien just use a 2x3 matrix.
but, that one isnt possible.
Yea I’m supposed to use gauss elimination. I wasn’t sure if I would just do a 2x3 matrix or if I needed to do something different to add that line
Nah, unless you are specifically using a program designed to do Gaussian eliminations you just use matrices.
Hey everyone. I don't understand the statement "Since MA> 0, the extremum points of the function d(x) and MA are the same". Why exactly we can conclude that?
Sorry for such weird typing, I used a translator to translate Russian into English from the image
That typography is truly bizarre.
But it must mean: Since MA(x)² = d(x) and MA(x) is always positive, the x that maximizes d(x) is the same as the x that maximizes MA(x).
(This is because the function that squares a number is strictly increasing on the positive reals).
@ruby cloud ^^
Tropo quick and random question. Are you a Ph.D student by any chance
Oh wow so ig ur a prof or some sort of researcher
Incredible
How do I do dis
first divide both isdes by 8 so u got cos(4x)=3/8 and then do inverse cos each sied so now u got 4x=arccos(3/8) and then divide by 4 so u got x=arccos(3/8)/4 and then plug into ur calculator
also remmeber to set to radians or degrees but idk what u doing
If you look at f(x)=x^2 then look at the increase that f(x+1) gives:
f(x+1) = (x+1)^2 = x^2+2x+1
f(x+1)-f(x) = (x^2+2x+1) - (x^2) = 2x+1
You should notice that the function increases by 2x+1 when going from f(x) to f(x+1). Meaning that the amount the function increases by increases as x gets bigger. Whereas if you compare g(x)=x to g(x+1)
g(x+1)=x+1
g(x+1)-g(x) = (x+1)-(x) = 1
You should see that the function only increases by a constant amount which isn't dependent on x.
I understand this isn’t a help channel but it won’t let me open a help channel 😭
is anyone available?
i might be able to help
but next time bro when you got a question just ask it otherwise then someone gotta respond to you first asking for the question and wait for u to respond back
first one a polynomial is continuous everywhere so u good
second one it should be continuous because the asymptote is at x=6 and theres no holes
third one no because its undefined at x=3
fourth one no because u got another undefined point
which also happens to be a hole
need help with this
ive had no problem with any problem so far, but this one is tripping me up
I have this equation, x^2 + y^3 = b^x. And i wanna find for what values of b (inequality) will give a graph with 3 roots. I started solving this with y as zero, yet im not exactly sure where to go next from this
,tex $x^2$ + $y^3$ = $b^x$
J_
im left with:
J_
You can check of trivial solutions via substitution, but the other solutions are non-elementary
so then is there another approach i could take to solving the problem
I can't think of any other than your approach
The reason why other solutions are non-elementary, is because when you solve the given equation:
Hm thats a shame
$x^2 = b^x$
$\implies ln(x^2) = ln(b^x)$
For $x > 0, 2lnx = xln(b)$
$\implies lnx - x\frac{lnb}{2} = 0$
$\implies xe^{-x\frac{lnb}{2}} = 1
=> (-x\frac{lnb}{2})e^{-x\frac{lnb}{2}} = -\frac{lnb}{2}$
𝓘 .
Hm
𝓘 .
Whose inverse, called the Lambert W function, is non-elementary
I mean there could be another approach of solving this
But currently I can't think of any
Thank you for your help
Also b>0 here (and when you solve it in the end using Lambert W, b has to be greater than or equal to e^(2/e) because to solve for ue^u = w, there is a restriction of w≥-1/e, for Real u and w)
How good or bad is the Baron's E-Z Precalculus book?
TheLord26
Compile Error! Click the
reaction for more information.
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Take the log of both sides, $\log(6^{1-8x})=log(7^{x})\(1-8x)(log(6))=xlog(7)$ from there, it’s a simple equation, expand brackets and do the logarithms.
TheLord26
wonky ahhh sin wave, also i cant see the equation.
hi i have a problem where i want a formula like:
formula(d, f(x)) = a
where f(a) is the smallest number where the number of digits in f(a) = d
is this possible?
for example:
let f(x) = n * (n+1) / 2
let d = 4
then formula(d, f(x)) = 45
because f(45) = 1035, which 1035 is the smallest number where the number digits of 1035 = d ( 4 )
can someone help me with this
Suppose a car is travelling 40 feet/sec and it loses control on wet asphalt. How long will its skid marks be?
The question is incomplete. What's the coefficient of kinetic friction and the mass of car?
0.5
And mass?
not given
solving it
i have to find the "How long will its skid marks be?"
and the answer should be stated with feet
Please send the complete question because it still seems incomplete. While skidding, is the car still being accelerated? Were brakes applied at that time?
I don't think there's really a formula but you can formulate an algorithm.
I'll give you a hint for this particular example: what are the roots of f(x) - 1000 in this case? (x in R, then subject the condition of x being a natural number)
I believe the assumption is that friction is the only (horizontal) force applied on the car
I also thought about that too, but it would be better if OP sends the full question
If you use the above assumption, then you want the car going with 40ft/s to come to a stop at 0ft/s. What do you think that caused this?
Well, just substitute the values in the given relation
I did but doesnt give the right answer
Could you please show your working
You are substituting the values in the relation incorrectly
The speed of the car while it was drifting is given 40ft/s
Yes
You have to find the distance d (i.e. the length of the skid mark)
And read this passage once more
log_10(n)+1, then just discard the decimal places.
also f(x)=x*(x+1)/2, dont yse n if you say f(x), use x or f(n).
y = 4 sin(16/9(x -3pi/8)) + 2
Plot (3pi/8, 0) and (3pi/2,0)
Hello
What’s the best way to cram for a pre calc test
do alot of exercises, like alot. Worked good enough for vectors
we have desmos at home
pull out the textbook and do as many problems as u can if u run outta problems to do find more
can anyone help me answer this rq <@&286206848099549185>
so first make a triangle with ur vector and 2 components
and with trig functions the x component will be 45m * cos61
the y component will be 45m * sin61
make sure ur calculator is in degrees too and not radians
preciate it
preciate it?
is the first one right or do you distribute the expontents and simplify
which
alr thanks
no problem mrverdevelt_43754
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Can someone explain why this is true:
Is it just a coincidence or is there a more general trigonometric relation that explains it
i gotchu
i am writing it on the online whiteboard so gimme a sec
wait i messed up somewhere
bro screw this i keep messign up the algebra
i will find out late
later
Thank you, but I was looking for the explanation of this relationship in a more general way. It seens odd to have two arbitrary tangents summing to an integer. I was wondering if there is a more general relation from which this equation is just an instance
There is no general solution. It’s just whether the output of the trig functions sum to an integer.
Hello, sorry for the ping but this is a followup to yestardays question
I think it might still involve Lambert but im not sure
,tex $x^2 + y^3 = b^x$
J_
For b = 2, will there be three roots on the graph?
Meaning three zeroes
I know there are, i just need help solving
Because im stuck on the step:
J_
And im not sure how to continue
There are actually multiple values of b for which the graph has 3 roots
Yes, but this hones in on just the value of b = 2 now
For simplicity of the question 😂
Well you can draw the graphs and count the intersection points
Yeah, but from like an algebraic standpoint
It may require slight amount of calculus
In my guidelines, i am allowed to look at graphs for inspiration, but need to solve this solely without that
From algebraic standpoint,
for x > 0
2lnx = xln2
=> lnx - x (ln2)/2 = 0
=> x e^(-x (ln2)/2) = 1
=> (-x (ln2)/2)e^(-x (ln2)/2) = -(ln2)/2
So still you have to use Lambert W
Hm, could you perhaps help me tweak this question to be able to solve without using Lambert W
So using intersection points from the graph and some basic knowledge calculus, you can solve this more easily
You can't really separate x here
Hm, would using Lambert W help me solve this question, like get a definitive answer
Also, do i need an indepth understanding of it?
Yeah
Is that Yeah to both questions
But it's not needed for you at this level, use graphs
Yep
Okay Hm
Thank you for your help
If this question didnt have
,tex $b^x$
and instead just b
Would it work?
J_
Yes
without lambert w*
Yea then i can sqrt easily
Yes, ±√b
Do you think that question would be too simple
Or is it in the slightest challenging
Thats a stupid question sorry
I mean it depends on context
In the actual question (not this one), is b just an integer?
Or a real number?
If b is an integer, it may become easier to solve
I assume b would be an integer
Then substitute values of b and find intersection points using graph
Yeah so use b as an integer then
Because for other non-integral real solutions of b, Lambert W would pop up
rllllyyyyy ???????