Finding the eq. of tangent line to this curve..

Hi! I'm struggling with this problem

Find an equation of the tangent line to the curve http://webquiz.ilrn.com/ilrn/formula...%7D%7D%7D&tr=1 at the point (1, 8).

I am stuck because while I'm solving this, I keep getting 0/0.

How would you solve this problem?

Thanks!

Re: Finding the eq. of tangent line to this curve..

1. Find the differentiated function.

2. put in the (x,y) in the f'(x).

3. write the slope-pt form.

Re: Finding the eq. of tangent line to this curve..

Rewrite as $\displaystyle y = 8x^{-\frac{1}{2}}$.

$\displaystyle \frac{dy}{dx} = -4x^{-\frac{3}{2}}$. At the point (1,8), $\displaystyle \frac{dy}{dx} = -4$.

Write the equation of the tangent line in point-slope form: $\displaystyle y - 8 = -4(x-1)$.