# Math Help - Tangent Line

1. ## Tangent Line

$y=\sqrt[3]{x}$

a) find the equation of the tangent line at the point P (-1, -1).

b) draw the graph of the curve and the tangent line at the point P.

My doubt is, how can i find the tangent line of that function if he don't pass in point P?

2. ## Re: Tangent Line

Originally Posted by Chipset3600

$y=\sqrt[3]{x}$

a) find the equation of the tangent line at the point P (-1, -1).

b) draw the graph of the curve and the tangent line at the point P.

My doubt is, how can i find the tangent line of that function if he don't pass in point P?
I'm sorry, I do not understand what do mean by the statement "if he don't pass in point P?"

To find the line tangent to the curve $f(x) = \sqrt[3]{x}$ at P(-1,-1) ...

1. find f'(x), then evaluate f'(-1) , the slope of the tangent line at point P.

2. Use the point-slope form of a linear equation ...

$y - (-1) = f'(-1)[x - (-1)]$

3. ## Re: Tangent Line

i found the equation: y= (x/3)-(2/3) but the graph was:

4. ## Re: Tangent Line

have a look at this graph ...

5. ## Re: Tangent Line

wow! but why my function appears only in 1st quadrant?

6. ## Re: Tangent Line

Originally Posted by Chipset3600
wow! but why my function appears only in 1st quadrant?
how are you inputting the cube root function?

7. ## Re: Tangent Line

Just Like you x^(1/3)

8. ## Re: Tangent Line

can't say why ... software issue?

here is the free grapher I use ...