Math Help
- Thread starter Azhria Lilu
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Moonlite Star
Cadet
lol that is so true...i hate cal...
M
mystery_chick
Guest
merging with Math help...
--mandy
--mandy
Moonlite Star
Cadet
Well, they give you the points of the three zeros of the graph, so you use those to find the equation. chookie was just using the zeros and multiplying them to get the final answer.
Zeros = -3, 2, and -1
y=x is the standard form where the zero is zero. shifts are added to the x to get the new zeros.
so you have y = (x - (-3)) * (x - (-1)) * (x-2) = - (x+3)*(x+1)*(x-2)
or expanded: y = -x^3 -2x^2 +5x +6
hope that makes more sense...altho ive found myself bad at explaining things...
um.....don't know how good my explaination might be but here it is:
The points you listed were the x and y intercepts.
Say in the case of a linear equation with (2,0) and (0,-6) as points we know that;
x intercept = 2
y intercept = -6
therefore the equation is y = a(x-2)
because when y = 0, x will be 2 no matter what ‘a’ stands for.
To find what ‘a’ is we sub x = 0 and y = - 6, solve the equation to find that a = 3.
……………………….
This same thing applies with cubic equation,
x intercept = -3, -1 and 2.
y intercept = 6
Equation is => y = a (x+3)(x+1)(x-2) since when y = 0, x can be -3, -1 or 2.
Now to find out what ‘a’ is just sub x = 0 and y = 6 and solve the equation to find that a = -1
………………………
the working out of graphs from equations and vice versa is heavily dependent on the intercepts and knowing what kind of graph or equation it is (ie cubic, linear…) then from there it’s just solving the algebra.
Hope I haven’t confused you.
The points you listed were the x and y intercepts.
Say in the case of a linear equation with (2,0) and (0,-6) as points we know that;
x intercept = 2
y intercept = -6
therefore the equation is y = a(x-2)
because when y = 0, x will be 2 no matter what ‘a’ stands for.
To find what ‘a’ is we sub x = 0 and y = - 6, solve the equation to find that a = 3.
……………………….
This same thing applies with cubic equation,
x intercept = -3, -1 and 2.
y intercept = 6
Equation is => y = a (x+3)(x+1)(x-2) since when y = 0, x can be -3, -1 or 2.
Now to find out what ‘a’ is just sub x = 0 and y = 6 and solve the equation to find that a = -1
………………………
the working out of graphs from equations and vice versa is heavily dependent on the intercepts and knowing what kind of graph or equation it is (ie cubic, linear…) then from there it’s just solving the algebra.
Hope I haven’t confused you.
M
mystery_chick
Guest
Okay need help.
Bill and Jill are hired to piant a line on a road. If Bill worked by himself, he could paint the line in B hours. If Jill worked by herself, she could paint the line in J hours. Bill starts painting the line from one end, and Jill begins paintingt he line fromt he other end one hour later. They both work until the line is painted. Which of the following is an expression for the number of hours that Bill works?
A) B(J+1) / B+J
B) J+1
C) [BJ / B+J] +1
D) ( B+ J - 1) / 2
E) B(J-1) / (B+J)
Help!
--mandy
Bill and Jill are hired to piant a line on a road. If Bill worked by himself, he could paint the line in B hours. If Jill worked by herself, she could paint the line in J hours. Bill starts painting the line from one end, and Jill begins paintingt he line fromt he other end one hour later. They both work until the line is painted. Which of the following is an expression for the number of hours that Bill works?
A) B(J+1) / B+J
B) J+1
C) [BJ / B+J] +1
D) ( B+ J - 1) / 2
E) B(J-1) / (B+J)
Help!
--mandy
Alias_Fan0202
Cadet
i'm getting B-J-1
but that's not right
hmmmmmmmmmm...
i'm sorry
but that's not right
hmmmmmmmmmm...
i'm sorry
M
Marlene
Guest
I need help!
Express each given function as a function of a positive acute angle.
cos 190
tan 260
sin (-340)
(There's a degree sign after the number.)
Quite frankly I just don't know the the heck the question is asking. Anyone care to explain?
That and how do you you find the exact numerical value of like sin 120 and sin of 150...like I know for like 30, 60, 90, and like 45, you can use those special right triangles and get it but like what about the rest of the stuff?
Thanks :marlene:
Express each given function as a function of a positive acute angle.
cos 190
tan 260
sin (-340)
(There's a degree sign after the number.)
Quite frankly I just don't know the the heck the question is asking. Anyone care to explain?
That and how do you you find the exact numerical value of like sin 120 and sin of 150...like I know for like 30, 60, 90, and like 45, you can use those special right triangles and get it but like what about the rest of the stuff?
Thanks :marlene:
M
mystery_chick
Guest
Marlene said:I need help!
Express each given function as a function of a positive acute angle.
cos 190
tan 260
sin (-340)
(There's a degree sign after the number.)
Quite frankly I just don't know the the heck the question is asking. Anyone care to explain?
That and how do you you find the exact numerical value of like sin 120 and sin of 150...like I know for like 30, 60, 90, and like 45, you can use those special right triangles and get it but like what about the rest of the stuff?
Thanks :marlene:
[post="1210133"]<{POST_SNAPBACK}>[/post]
Positive actue angle
:blink: I don't think you can express cos 190 as a function of a positive acute angle. :blink: what we use is the winding function, where W (0) = 0 degrees and W(pi) = 180 degrees. so cos 190 =W (19/18 pi) which I don't think it's what your'e looking for. well okay, cos 190 is -cos 10 right? but that's just wierd. As for the exact value, there's no way to "find out" but there are points that you can remember.
W(0) = 0 degrees = (cos (0), sin(0)) = 1,0
W(pi/6) = 30 degrees = root3/2 , 1/2
W(pi/4) = 45 degrees = 1/sqrt 2 , 1/sqrt 2
W(pi/3) = 60 degrees = 1/2 , root3/2
w(pi/2) = 90 degrees = 0,1
it's a lot easier to understand, when you draw a circle of radius 1 with the center at the origin.
Hope that helps.
--Mandy
M
Marlene
Guest
okay...:walks away: Winding functions?!?!? :dies: I loathe math... but thanks for adding to the utter confusion manders!
:dies: I loathe math... but thanks for adding to the utter confusion manders!
M
mystery_chick
Guest
Marlene said:okay...:walks away: Winding functions?!?!?
[post="1210784"]<{POST_SNAPBACK}>[/post]
:lol: I'm sorry,
but that's how I learned it so... okay I kinda feel pathetic quoting myself but I REALLY need help with this
mystery_chick said:Okay need help.
Bill and Jill are hired to piant a line on a road. If Bill worked by himself, he could paint the line in B hours. If Jill worked by herself, she could paint the line in J hours. Bill starts painting the line from one end, and Jill begins paintingt he line fromt he other end one hour later. They both work until the line is painted. Which of the following is an expression for the number of hours that Bill works?
A) B(J+1) / B+J
B) J+1
C) [BJ / B+J] +1
D) ( B+ J - 1) / 2
E) B(J-1) / (B+J)
Help!
--mandy
[post="1209926"]<{POST_SNAPBACK}>[/post]
please? someone?! anyone?!
--Mandy
Moonlite Star
Cadet
mystery_chick said:Okay need help.
Bill and Jill are hired to piant a line on a road. If Bill worked by himself, he could paint the line in B hours. If Jill worked by herself, she could paint the line in J hours. Bill starts painting the line from one end, and Jill begins paintingt he line fromt he other end one hour later. They both work until the line is painted. Which of the following is an expression for the number of hours that Bill works?
A) B(J+1) / B+J
B) J+1
C) [BJ / B+J] +1
D) ( B+ J - 1) / 2
E) B(J-1) / (B+J)
Help!
--mandy
[post="1209926"]<{POST_SNAPBACK}>[/post]
What section/unit are you working on in math? I mite be able to help if I know how to start off the problem...
Marlene said:I need help!
Express each given function as a function of a positive acute angle.
cos 190
tan 260
sin (-340)
(There's a degree sign after the number.)
Quite frankly I just don't know the the heck the question is asking. Anyone care to explain?
That and how do you you find the exact numerical value of like sin 120 and sin of 150...like I know for like 30, 60, 90, and like 45, you can use those special right triangles and get it but like what about the rest of the stuff?
Thanks :marlene:
[post="1210133"]<{POST_SNAPBACK}>[/post]
I'm going to assume you haven't learned the unit circle yet...
for sin 120 and anything not a special angle...you'll have to use a calculator, as far as I know. You'll probably be using a the calc for a while to find those numbers. But then again, who knows--maybe you'll learn how next year if you have a really nice teacher that can teach you!
lol I still haven't learned yet...As for the question itself, I think it's just asking you to find the angle it's "equal" to. so you would just keep subtracting 90 degrees from it until you have a number that's positive and under 90 degrees. Not too complicated really.
Err, I hope it helps anyway...
---------------------------------------------------------
Now I need help from anyone who can...lol.
You are videotaping a race from a stand 132 ft from the track, following a car that is moving at 180 mi/h (264 ft/sec). How fast will the camera angle (theta) be changing when the car is right in front of you? A half second later?
Pic:
[attachment=16563:attachment]
I'm working with related rates right now...
M
mystery_chick
Guest
no idea.
and it's not a "unit" it's a contest question. We're prepping for the Fermat contest so.. ya.
--mandy
and it's not a "unit" it's a contest question. We're prepping for the Fermat contest so.. ya.
--mandy
Moonlite Star
Cadet
sounds fun...lol.
do you have the correct answers?
lets see what can be done then...
Lol...I googled the problem and found it online. And the answers... I'm not taking credit for it, but here's what someone else posted in another forum!
do you have the correct answers?
lets see what can be done then...
Lol...I googled the problem and found it online. And the answers...
I'm not taking credit for it, but here's what someone else posted in another forum!
