The Student Room Group
Competition - post a photo you've taken of nature >>
Competition - post a photo you've taken of nature >>
Competition - post a photo you've taken of nature >>

C4 differentiation help!

Hey!

The question is:

Find the equation of the normal to the curve with parametric equations x=e^t,
y= e^t + e^-t, at the point P, where t= 0.

Here's what i get,
dx/dt = e^t. dy/dt = e^t - e^-t

when you dy/dx it and substitute t=0, the dy/dx= 0 since dy/dx = (e^t - e^-t)/e^t.... Right?

So, how do i get the equation of normal when the gradient of tangent is zero? :colondollar:
Original post by ACatCalledMeow
Hey!

The question is:

Find the equation of the normal to the curve with parametric equations x=e^t,
y= e^t + e^-t, at the point P, where t= 0.

Here's what i get,
dx/dt = e^t. dy/dt = e^t - e^-t

when you dy/dx it and substitute t=0, the dy/dx= 0 since dy/dx = (e^t - e^-t)/e^t.... Right?

So, how do i get the equation of normal when the gradient of tangent is zero? :colondollar:


If the gradient of the tangent is zero, then it is parallel to the x axis. So the normal must therefore be parallel to the y axis. So you just need to find an x value.
Original post by Freerider101
If the gradient of the tangent is zero, then it is parallel to the x axis. So the normal must therefore be parallel to the y axis. So you just need to find an x value.


Why didn't i think of that? :colondollar::colondollar:

THANKS! ahhhhh feel so stupid now. Thanks again! :biggrin:

Quick Reply

Related discussions

Latest

Trending

Trending

Articles for you