Question

Evaluate the integral x cos5x dx

Answer 1

okay so I need to do integration by parts

Answer 2

u = x and dv = cos5x

Answer 3

then du = 1 and v = -\[\frac{ 1 }{ 5 } \sin 5x\]

Answer 4

i think

Answer 5

wait no negative

Answer 6

we use the forumla \[uv - \int\limits_{}^{}v du\]

Answer 7

so I think I get \[\frac{ 1 }{ 5 }x \sin(5x) + \frac{ 1 }{ 25 } \cos(5x) + c\] but I am not sure