Question

A value that satisfy cos square x - 2 cos x is equal to zero in degrees

Answer 1

Step-by-step explanation:

${ (\cos(x)) }^{2} - 2 \cos(x) = 0 \\ = > \cos(x) ( \cos(x) - 2) = 0 \\ = > cosx = 0 \: or \: 2$

But we know cosx is never equal to 2.

because,

$- 1 \leqslant \cos(x) \leqslant 1$

$= > \cos(x) = 0 = \cos(0°) \\ = > x = 0°$

Answer 2

Answer:

90 degrees

Step-by-step explanation:

cos^2 x - 2cosx = 0

Let x = 90

then,

cos^2 90 degrees - 2cos90 degrees = 0           [because cos90 = 0]

=>  0^2 - 2(0) = 0

=>  0 - 0 = 0