Question

11. If tan A =1/7 and tan B =1/3 show that cos 2A = sin 4B.​

Answer 1

Answer:

Cos 2A=sin 4B

cos^2 A-sin^2 A=4sinBcosB(cos^2 B-sin^2 B) ::equation

tanA=1/7

so cosA=7/5root2

sinA =1/5root2

cosB=3/root10

sinB=1/root10

so apply these value in above equation

hence LHS=RHS