Processing math: 100%
Home / Aptitude Tests / Mathematics / If x + y = 90 simpli...
If x + y = 90 simplify (sinx+siny)2−2sinxsiny...

If x + y = 90 simplify (sinx+siny)2−2sinxsiny

A.

1

B.

0

C.

2

D.

-1

Correct answer is A

Given: x+y=90°...(1)

(sinx+siny)22sinxsiny=sin2x+sin2y+2sinxsiny2sinxsiny

= sin2x+sin2y...(2)

Recall: sinx=cos(90x)...(a)

From (1), y=90x...(b)

Putting (a) and (b) in (2), we have

sin2x+sin2ycos2(90x)+sin2(90x)

= 1