Decide whether the expression is or is not an identity.
-$$\sqrt { 1 - \cos ^ { 2 } x } = \sin x$$
A) Identity
B) Not an identity

Name: Decide whether the expression is or is not an identity. -\[\sqrt { 1 - \cos ^ { 2 } x } = \sin x\] A) Identity B) Not an identity
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Question

Quizplus · Accepted Answer

The expression is not an identity because $\sqrt { 1 - \cos ^ { 2 } x }$ simplifies to $|\sin x|$, not $\sin x$. The square root ensures the left side is always non-negative, while $\sin x$ can be negative depending on the value of $x$.

Decide Whether the Expression Is or Is Not an Identity 1−cos⁡2x=sin⁡x\sqrt { 1 - \cos ^ { 2 } x } = \sin x1−cos2x​=sinx

Decide Whether the Expression Is or Is Not an Identity $\sqrt { 1 - \cos ^ { 2 } x } = \sin x$