4cos 105 *cos 15 +1=0 prove that
Answers
Answered by
0
Answer:
sorry mate.... am just 13..years old.. IMAO idk all the stuff
Answered by
6
Answer:
L.H.S
4 cos 105 × cos 15 + 1
= 4 cos (90+15) × cos 15 + 1
= 4 (-sin 15) × cos 15 + 1
= 1 - 4 sin 15 × cos 15
= 1 - 2 × 2 sin 15 × cos 15
= 1 - 2 × sin (2 × 15)
= 1 - 2 × sin 30
= 1 - 2 × 0.5
= 0 = R.H.S (Proved)
Similar questions