Answer:
hence cos ( 2 A ) = cos 2 A − ( 1 − cos 2 A ) = 2 cos 2 A − 1
Step-by-step explanation:Well we know that for two angles A , B
it holds that cos ( A + B ) = cos A cos B − sin A ⋅ sin B hence for A = B you get cos ( 2 A ) = cos 2 A − sin 2 A But sin 2 A = 1 − cos 2 A
OPTION:
B
Step-by-step explanation:
Answer:

Step-by-step explanation:
Factor the numerator and cancel common factors from numerator and denominator.

Answer:
x = 16
Step-by-step explanation:
Use that the addition of all internal angles of a triangle must add up to 180, and the fact that the two given triangles are similar:
51 + 65 + 4 x = 180
combine and solve for "x"
116 + 4 x = 180
4 x = 180 - 116
4 x = 64
x = 64 / 4
x = 16
Answer:

Step-by-step explanation:

