Calculus problems.

Okay 4chan. I need help with calculus.
Here's your mission: find the derivative using the product rule. Simplify your answers.
f(x)= x^2(x^3+1)
f(x)= x(5x^2-1)
f(x)= (x^2+x)(3x+1)
Also, show your work so I can do the rest of these problems. Thank you.

Okay.
f(x)= x^2(x^3+1)
f(x)= 2x(x^3+1)+x^2(3x^2+1)
f(x)= 2x^4+2x + 3x^4+x^2
f(x)= 6x^4+2x+x^2
The answer, according to the book, is 6x^4+2x. I dunno where I got x^2.