checking a problem/answer

[Ilovemymom]

Find the equation of the tangent line to the curve when x has the given value.

f(x) = x^3/4 ; x = 8


I got y = 16x + 256

 

[stapel]

Please clarify the function. Is it "f(x) = (x³)/4", or is it "f(x) = x^3/4"?

Thank you.

Eliz.

 

[Unco]

Find the equation of the tangent line to the curve when x has the given value.

f(x) = x^3/4 ; x = 8


I got y = 16x + 256

Differentiate (I think you may have forgotten to multiply by the power (3) ), plug in x=8 to find the slope of the curve at x=8.

Use the curve's equation to find the y-ordinate at x=8, and plug all this into the slope-point equation to find the equation of the tangent.

 

[Ilovemymom]

thanks I did mess up.

y= 48x-256

 

[Unco]

That's correct.