Q.

If   A=1π[sin-1(πx)tan-1(xπ)sin-1(xπ)cot-1(πx)],   B=1π[-cos-1(πx)tan-1(xπ)sin-1(xπ)-tan-1(πx)],

then A-B is equal to:

1 I  
2 O  
3 2I  
4 12I  

Ans.

(4)

Ans.    12I

Explanation:

We have,

                B=[-1πcos-1(πx)1πtan-1(xπ)1πsin-1(xπ)-1πtan-1(πx)]

and         A=[1πsin-1(πx)1πtan-1(xπ)1πsin-1(xπ)1πcot-1(πx)]

∴   A-B=[1π(sin-1(πx)+cos-1(πx))001π(cot-1(πx)+tan-1(πx))]

                    =[1π·π2001π·π2]=12[1001]=12I