Question

Help with calculus please?

Answer 1

Wait let me know that the .12 means in the first question and i will fix the answer

int (x)(cosx) dx 

u=x      ----> take derivative     du=dx
dv=cosx    -----> take integral  v=sinx

now use integration by parts 

u v - int (v)du
x sinx - int (sinx) (1) dx=

x sinx  - (-cos(x)) + c =

answer is = x sinx + cosx + c