Complete the sentence so the result is an identity. Let x be any real number.
-$$\sqrt { 1 - \cos ^ { 2 } x } = 1 - \cos x$$
A) Not an identity
B) Identity

Question

Quizplus · Accepted Answer

The correct expression should be $\sqrt { 1 - \cos ^ { 2 } x } = \sin x$, not $1 - \cos x$. This is because $\sin^2 x + \cos^2 x = 1$, so $\sqrt { 1 - \cos ^ { 2 } x } = \sin x$, which means the given equation is not an identity for all values of $x$.

Complete the Sentence So the Result Is an Identity 1−cos⁡2x=1−cos⁡x\sqrt { 1 - \cos ^ { 2 } x } = 1 - \cos x1−cos2x​=1−cosx

Complete the Sentence So the Result Is an Identity $\sqrt { 1 - \cos ^ { 2 } x } = 1 - \cos x$