Question

Find value of (sin theta + cos theta)^2 + (cos theta - sin theta)^2

Answer 1

Heya.....

(Sin theta +cos theta)^2=
sin^2theta+cos^2theta+tsin theta cos theta

Using[(a+b)^2=a^2+b^2+2ab]

(Cos theta-sin theta)^2=
Cos^2theta+sin^2theta-tsin theta cos theta

Adding both....

2(cos^2 theta+sin^2theta)
[using sin^2theta+cos^2theta=1]
=2×1
=2

@skb