Question

tan-1x +cot-1

x=_____

(a) 1 (b) 0 (c) 900

(d) 450

Answer 1

tan^(-1)x + cot^(-1)x = π/2=90°,

ok so now lets prove it

let tan^(-1)x =A,

then

tanA=x,

we can write it as

cot(90°-A)=x, (since tan@=cot(90°-@),

(90°-A)=cot^(-1)x,

now put the value of A here, we get

90° - tan^(-1)x = cot^(-1)x,

hence

90° = tan^(-1)x + cot^(-1)x,

hope u understand........thanxxxx