Question

The solution to the the antiderivative problem
Sf(x) dx turned out to be sinx 􀀀- xcos x + C. What is f(x)?

Answer 1

used the derivative with respect to x of that function to come up with -xsinx

Answer 2

oops, looks like it's supposed to be xsinx...is that right?

Answer 3

you need to do the reverse - that is find the derivative of sin x - x cosx

Answer 4

you can find the derivative of x cos x by using the Product Rule

Answer 5

cleetus779, you are correct

if y = sin(x) - x*cos(x), then dy/dx = x*sin(x)

so that's why \[\Large \int x\sin(x)dx = \sin(x) - x\cos(x)\]

Answer 6

oops plus C of course

Answer 7

d(x cosx) dx = x * -sinx + cos x

Answer 8

thanks for checking guys

Answer 9

yw