InterviewSolution
Saved Bookmarks
| 1. |
Evaluate:`int(cosx)/(sin(x-pi/6)sin(x+pi/6))dx` |
|
Answer» ` I =int(cosx)/(sin(x-(pi)/(6))sin(x+(pi)/(6)))dx` `=int(cosx)/(sin^(2)x-"sin"^(2)(pi)/(6))dx` Let `sinx=t` or `dt=cosx dx` ` :. I=int(dt)/(t^(2)-(1)/(4))` `=(1)/(2(1)/(2))log|(t-(1)/(2))/(t+(1)/(2))|+C` `=log|(2t-1)/(2t+1)|+C` `=log|(2sinx-1)/(2sinx+1)|+C` |
|