# Equations and tangents!!

• Oct 20th 2013, 12:44 AM
MrsQueenBee123
Equations and tangents!!
A curve has equation y=7-2x^5

Find an equation for the tangent to the curve at the point where x=1.
• Oct 20th 2013, 02:23 AM
Prove It
Re: Equations and tangents!!
What have you tried so far?
• Oct 20th 2013, 09:31 AM
Re: Equations and tangents!!
The tangent is simply the value of the derivative at x=1. So first you have to know if the function y=-2x^5+7 is derivable at x=1 . If it is it should yield the value of the tangent.

So it should be something like the tangent at a point let's say x0 is simply f'(x0).
• Oct 20th 2013, 03:19 PM
Prove It
Re: Equations and tangents!!
Quote:

Originally Posted by SMAD
The tangent is simply the value of the derivative at x=1. So first you have to know if the function y=-2x^5+7 is derivable at x=1 . If it is it should yield the value of the tangent.

So it should be something like the tangent at a point let's say x0 is simply f'(x0).

No, that is incorrect. The tangent is the LINE that touches the original curve at the point specified. The derivative merely gives the GRADIENT of the tangent. So more work will be required to get the tangent once the gradient has been found.

Now the OP can show some effort before we give any more guidance.
• Oct 20th 2013, 03:55 PM
votan
Re: Equations and tangents!!
Quote:

Originally Posted by SMAD
The tangent is simply the value of the derivative at x=1. So first you have to know if the function y=-2x^5+7 is derivable at x=1 . If it is it should yield the value of the tangent.

So it should be something like the tangent at a point let's say x0 is simply f'(x0).

Prove It gave you a good hint to start. Do you know what the gradient of the tangent means? He pointed out to you the tangent is a line. Here are your two points to think of: relate the gradient of the tangent to one of the forms of an equation of a line. Go.