Factor the trigonometric equation. cos2x-cosx

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.

the direct variation says that:

then the equation is of the form is given by:

            where k is the constant variation.

from the given table:

consider any value of x and m(x)=y

x = 2 and m(x)=y = 3

substitute these value in [1]; we have;

divide both sides by 2 we get;

⇒

check:

put x = -1 and m(x) = -1.5

substitute in the equation:

-1.5 = -1.5                   true

therefore, the function m(x) represents a direct variation

graph of this function as shown below: