Answer:
<h2>11.1111111111 or 1.1 <-(rounded)</h2>
Step-by-step explanation:
4+6+7+7+11+12+15+18+20= 100
divide by the number of values we have. we have 9 values
100/9=11.1111111111
I hope this helped
Cos(2x) = cos^2(x) - sin^2(x) - cos(x)
but sin^2(x) = 1 - cos^2(x)
cos(2x) - cos(x) = cos^2(x) - (1 - cos^2(x) ) - cos(x)
cos(2x) - cos(x) = cos^2(x) - 1 + cos^2(x) - cos(x)
cos(2x) - cos(x) = 2cos^2(x) - 1 - cos(x)
cos(2x) - cos(x) = (2cos(x) + 1)(cos(x) - 1)
I think this is what you have asked for.
