2cos^2 x = 1 + cos 2x
cos^2 x = 1/2(1 + cos 2x)
f(x) = 6cos^2 x - 4 sin 2x = 6(1/2(1 + cos 2x) - 4 sin 2x = 3 + 3cos 2x - 4sin 2x
So... hmmm if you check the first picture below, for 2)
we could use the proportions of those small, medium and large similar triangles like

now.. for 3) will be the second picture below
In a parallelogram, opposite angles are congruent.
Since angles z and 124° are opposite angles in the parallelogram, they are congruent angles.
Therefore we have:
Answer:
40 minutes
2/3 hours
0.667 hour
2,400 seconds
Step-by-step explanation: