Question

1 + cos 56° + cos 58º – cos 66°
=

Answer 1

1+ cos 56 = 2 cos^2 28 as cos 2t = 2 cos^2 t - 1 cos 58 = 2 cos^ 29 - 1 cos 66 = 2cos ^2 33 - 1 so 1+ cos 56 + cos 58 - cos 66 = 2 cos^2 28 + 2 cos^2 29 - 2 cos^2 33 = 2 ( cos^2 28 + cos ^2 29 - cos ^2 33)

now 28+29+33 = 90 in case we demonstrate cos ^2 A + cos^2 B - cos^2 c = 2 cos A cos B sin C when A+B+C = pi.2

Aapko India ki kasam mujhe brainliest mark Kar dena.

Answer 2

Answer:

Step-by-step explanation: 1 +cos 56°+ cos 58°-cos 66° is equal to

1+cos 56=2cos^228 as cos 2+=2 cos^2+-1 cos 58=2 cos^ 29-1 cos 66=2cos^ 233-1

Pls mark me brainliest