Question

Question #858a2

Answer 1

`cos 87/(cos 77)`

Explanation:

From trig identity: cos 2a = 1 - 2cos^2 a, we get
1 - 2cos^2 (43.5) = cos 87
Note that:
sin 6 = cos (90 - 6) = cos 84
sin 277 = sin (7 + 270) = - cos 7
The denominator transforms itself to:
sin 84 sin 7 + cos 84 cos 7 = cos (84 - 7) = cos 77
The value of the trig function is:
`cos 87/cos 77`
I can't go further.