Question

Which of the following is a solution to 2cos^2x– 2 = 0 ?

Answer 1

Answer:

A and C

Step-by-step explanation:

Given

2cos²x - 2 = 0 ( add 2 to both sides )

2cos²x = 2 ( divide both sides by 2 )

cos²x = 1 ( take the square root of both sides )

cos x = ± $\sqrt{1}$ = ± 1

cos x = 1 ⇒ x = $cos^{-1}$(1) = 0°

cos x  = - 1 ⇒ x = $cos^{-1}$(- 1) = 180°

Answer 2

Answer:

2 possible results

0° and 180°

Step-by-step explanation:

2cos² x– 2 = 0  (add 2 to both sides)

2cos² x = 2  (divide both sides by 2)

cos² x = 2/2

cos² x = 1

cos x = ±√1

cos x = ±1

because the range of x is not stated, there are 2 possible results for x  that will cause cos x to be either 1 or -1

0° and 180°