She ran the last 100 meters in 2:15 -1:25 = 0:50, so her average speed was
... (100 m)/(50 s) = 2.0 m/s
The answer is b (I think not really sure)
We are asked to express cos^ 3 x in terms of powers of trigonometric functions not greater than 1
cos ^ 3 x is equal to cos x * cos^2 x.
<span>cos^2 x = 1 - sin^2 x.
</span>sin^2 x = (1 - cos 2x) /2
the answer is cos ^ 3 x = cos x * (1 - <span> (1 - cos 2x) /2 )</span>
I think that it would be a
