[Solved] Integration by Parts (Why changing u and dv get the wrong answer)
Hi, my question is the from t=1 to t = 4: Integral sqrt(t)ln(t)dt
On my first try I used, u =sqrt(t) dv=ln(t)dt du=1/2t^(-1/2) v = 1/t
My answer at the end was 1-2=-1
^ this is wrong by my online homework.
But this time i switched the u and dv where, u = ln(t) dv=sqrt(t)dt du = 1/t dt v= 2/3t^(3/2)
My answer at the end was 4.28246
^ this answer is correct..
I don't want to use the LIATE rule of thumb. But, I want to know why the other answer didn't work although I used the proper steps.
Can you not have negative answer when using Integration by Parts?
Hi, my question is the from t=1 to t = 4: Integral sqrt(t)ln(t)dt
On my first try I used, u =sqrt(t) dv=ln(t)dt du=1/2t^(-1/2) v = 1/t
My answer at the end was 1-2=-1
^ this is wrong by my online homework.
But this time i switched the u and dv where, u = ln(t) dv=sqrt(t)dt du = 1/t dt v= 2/3t^(3/2)
My answer at the end was 4.28246
^ this answer is correct..
I don't want to use the LIATE rule of thumb. But, I want to know why the other answer didn't work although I used the proper steps.
Can you not have negative answer when using Integration by Parts?
Last edited: