1.

`int(1)/(tanx+cotx+secx+"cosec "x)dx` is equal toA. `(1)/(2)(sinx+cosx+x)+C`B. `(1)/(2)(sinx-cosx-x)+C`C. `(1)/(2)(cosx-xsinx)+C`D. none of these

Answer» Correct Answer - d
Let `=int(1)/(tanx+cotx+secx+"cosec " x)dx` Then ,
`I=int(sinxcosx)/(1+sinx+cosx)dx`
`rArrI=(1)/(2)int((1+2sinx cosx-1))/(1+sinx+cosx)dx=(1)/(2)int((sinx+cosx)^(2)-1)/(1+sinx+cosx)`
`rArr I=(1)/(2)int((sinx+cosx+1)(sinx+cosx-1))/(1+sinx+cosx)dx`
`rArr I=(1)/(2)int(sinx+cosx-1)dx`
`rArrI=(1)/(2)(-cosx+sinx-1)+C`


Discussion

No Comment Found

Related InterviewSolutions