Question

Find the area of the surface obtained by rotating the curve y=4x^3 from x=0 to x=4 about the x-axis

Answer 1

the derivative of 4x^3 is 12x^2

Answer 2

correct how do i find dy/dx?

Answer 3

it is d(4x^3)/dx

Answer 4

ok so dx is the derivative or what?

Answer 5

you have the formula okay, now all you have to do is plug in 12x^2 where it says dy/dx and where it has a y plug in 4x^3 then evaluate that

Answer 6

\[2\pi 4x ^{3}\sqrt{1+(12x^2)^{2}}dx\]

Answer 7

looks good

Answer 8

thanks