Question Number 131275 by Engr_Jidda last updated on 03/Feb/21

Answered by Ar Brandon last updated on 03/Feb/21
![℧=∫_0 ^4 ϱ^(2t) B_m B_n sin(((mπ)/4)t)sin(((nπ)/4)t)dt =−((B_m B_n )/2)∫_0 ^4 ϱ^(2t) {cos((((m+n)π)/4)t)−cos((((m−n)π)/4)t)}dt =−((2B_m B_n )/π)∫_0 ^π ϱ^((8u)/π) [cos((m+n)u)−cos((m−n)u)]du =−((2B_m B_n )/π){[cos((m+n)u)−cos((m−n)u)]ϱ^((8u)/π) ∙(π/8) −∫[(m−n)sin((m−n)u)−(m+n)sin((m+n)u)]((πϱ^((8u)/π) )/8)}_0 ^π =((2B_m B_n )/π)∫[(m−n)sin((m−n)u)−(m+n)sin((m+n)u)]((πϱ^((8u)/π) )/8)du =((2B_m B_n )/π){[(m−n)sin((m−n)u)−(m+n)sin((m+n)u)]((π^2 ϱ^((8u)/π) )/(64)) −∫{(m−n)^2 cos((m−n)u)−(m+n)^2 cos((m+n)u)}((π^2 ϱ^((8u)/π) )/(64))du}_0 ^π =0](https://www.tinkutara.com/question/Q131278.png)
Commented by Engr_Jidda last updated on 03/Feb/21

Commented by Ar Brandon last updated on 03/Feb/21
��I don't really know Sir. I'm a student. I just solved the calculus and left the conclusion to be made by you. Assuming you have studied the topic��
Commented by Engr_Jidda last updated on 03/Feb/21
