Question

.Solve the question A of this copy
I will mark as brainlist answer ​

Answer 1

Answer:

Hello,

tanA = b/a

clearly, sinA =b...... (1) & cosA=a

Now , ......(2)

L.H.S = a cos2A + b sin2A

= a cos^2 A -a sin^2 A+b × 2 sinA cosA

= a (a)^2 -a (b)^2+b×2×b×a

[ using (1)&(2)]

= a^3-ab^2+2ab^2

= a^3 + ab^2= a (a^2+b^2)

=a(cos^2 A+sin^2 A)=a×1= a= R.H.S

Hence proved......

Thank you!!

proved by @ jk