Question

h(x)=xcot(8sqrt(x))+20. Find the derivative.

Answer 1

My question is why we use the product rule, instead of the chain rule.

Answer 2

Because isn't it cotangent of x, which in this case is (8(sqrt(x)))?

Answer 3

It's not cot times that, because cot means nothing by itself i thought? Must be of something.

Answer 4

h(x)=xcot(8sqrt(x))+20
let u = x and v = cot(8sqrt(x))
that's why u have to use the product rule
h ' = u'v + uv'

Answer 5

Oh i see, i was letting u=xcot and v=(8sqrtx)

Answer 6

to get v', use the chain rule

Answer 7

I see now.

Answer 8

Thanks

Answer 9

hehe, welcome :)