Help on Tangent Line

N

nikchic5

Junior Member
Joined
Feb 16, 2006
Messages
106
Hello I have a question from my homework that I need help with...

(a) The curve with the equation y^2=5x^4-x^2 is called the Tschirnhausen cubic. Find an equation of the tangent line to the curve of the point (1,2).
(b) Illustrate part a by graphing the curve and the tangent line on the common screen.

Part b I can do I just need help with part a. Thank you very very much for your help!
 
y^2=5x^4-x^2
2y dy=(20x^3-2x) dx
dy/dx = (20x^3-2x)/2y =
(20x^3-2x)/2sqrt(5x^4-x^2)
 
Sorry...

I am soo sorry. I gave you the wrong equation. The right equation is
y^2= x^3 + 3x^2

Thank you and sorry about that!
 
That should still show how to solve it. You can now demonstrate that you understand. What do you get? Show your work.
 
Is this right?

Is this the correct answer...

2y y' = 3x^2 +6x
y' = (3x^2 + 6x) / (2y)
 
Nope, you didn't take the derivitive of the RHS. Look again at what I did.
 
You got it except you forgot it is /2y
-------------
Gene
 
I edited my reply. You are too fast for me.
PS and you forgot the sqrt.
 
You must log in or register to reply here.
Top