Re: Maths ! help !

Posted by Deepak_Ka on Apr 21, 2014; 6:06am
URL: http://discussion-forum.276.s1.nabble.com/Maths-help-tp7587407p7587505.html

Came across this ques in IGIDR sample paper:

x=sin(2pie/7)+sin(4pie/7)+sin(8pie/7)
y=cos(2pie/7)+cos(4pie/7)+cos(8pie/7)

The value of x^2+y^2 is :
a.2
b.3
c.4
d.1
e.NOTA

Answer is : a.)2

How do I go about exactly so that in x^2+y^2 I have no term involving the angle is sin or cos in form of pie/7??