`intsec^(4)xtanxdx=?`A. `(1)/(2)sec^(2)x+(1)/(4)sec^(4)x+C`B. `(1)/(2)tan^(2)x+(1)/(4)tan^(4)x+C`C. `(1)/(2)secx+log|secx+tanx|+C`D. none of these

`intsec^(4)xtanxdx=?`A. `(1)/(2)sec^(2)x+(1)/(4)sec^(4)x+C`B. `(1)/(2)

1.	`intsec^(4)xtanxdx=?`A. `(1)/(2)sec^(2)x+(1)/(4)sec^(4)x+C`B. `(1)/(2)tan^(2)x+(1)/(4)tan^(4)x+C`C. `(1)/(2)secx+log\|secx+tanx\|+C`D. none of these
Answer» Correct Answer - B `I=intsec^(2)xsec^(2)xtanxdx`. `=intsec^(2)x(1+tan^(2)x)tanxdx=int(1+t^(2))tdt`, where tan x=t `int(t+t^(3))dt=(t^(2))/(2)+(t^(4))/(4)+C=(1)/(2)tan^(2)x+(1)/(4)tan^(4)x+C`.