∫cottan−1x4cosec2tan−1xdx1+x2tan−1x=
5cot5cot−1x+C
−5cot5cot−1x+C
15cot5tan−1x+C
−15cot5tan−1x+C
T=∫cottan−1x4cosec2tan−1xdx1+x2tan−1x
Put tan−1x=y
T=∫coty4cosec2ydx
Put coty=z
cosec2ydy=−dzT=∫z4(−dz)=−z55+C=−15(coty)5+C=−15cot5tanh−1x+C