(cos alpha + cos beta )^2 + (sin alpha + sin | vedclass

Name: Exam Paper Generator | JEE NEET Paper Generator | Vedclass
Brand: Vedclass
Rating: 5 (35 reviews)

Question

(A) Expand the squares:$(\cos ^2 \alpha + \cos ^2 \beta + 2\cos \alpha \cos \beta) + (\sin ^2 \alpha + \sin ^2 \beta + 2\sin \alpha \sin \beta)$Group

Vedclass · Accepted Answer

$4\cos ^2\left( \frac{\alpha - \beta }{2} \right)$

Vedclass · Answer

(A) Expand the squares:$(\cos ^2 \alpha + \cos ^2 \beta + 2\cos \alpha \cos \beta) + (\sin ^2 \alpha + \sin ^2 \beta + 2\sin \alpha \sin \beta)$Group the terms using the identity $\sin^2 	heta + \cos^2 	heta = 1$:$(\cos^2 \alpha + \sin^2 \alpha) + (\cos^2 \beta + \sin^2 \beta) + 2(\cos \alpha \cos \beta + \sin \alpha \sin \beta)$$= 1 + 1 + 2\cos(\alpha - \beta)$$= 2 + 2\cos(\alpha - \beta)$$= 2(1 + \cos(\alpha - \beta))$Using the identity $1 + \cos(2	heta) = 2\cos^2 	heta$,we get:$= 2(2\cos^2(\frac{\alpha - \beta}{2}))$$= 4\cos^2(\frac{\alpha - \beta}{2})$.

$(\cos \alpha + \cos \beta )^2 + (\sin \alpha + \sin \beta )^2 = $

Similar Questions

If $\sqrt x + \frac{1}{{\sqrt x }} = 2\cos \theta ,$ then ${x^6} + {x^{ - 6}} = $

If $y = (1 + \tan A)(1 - \tan B)$ where $A - B = \frac{\pi}{4}$,then $(y + 1)^{y + 1}$ is equal to

If $\cos x + \cos y + \cos \alpha = 0$ and $\sin x + \sin y + \sin \alpha = 0,$ then $\cot \left( \frac{x + y}{2} \right) = $

If $x = \sin 130^\circ \cos 80^\circ$,$y = \sin 80^\circ \cos 130^\circ$,and $z = 1 + xy$,which one of the following is true?

Which of the following is correct?

Vedclass Test Series

Exam Paper Generator

Online Exam Module