Mathematics

The derivative of $\sin x$ is $\cos x$—a fact you can verify by thinking about how the slope of the sine curve changes as you move along it. So this problem reduces to evaluating $\cos\left(\frac{\pi}{6}\right)$, which is a standard angle whose cosine value you should know or be able to find on the unit circle.

The derivative of $\sin x$ is $\cos x$—a fact you can verify by thinking about how the slope of the sine curve changes as you move along it. So this problem reduces to evaluating $\cos\left(\frac{\pi}{6}\right)$, which is a standard angle whose cosine value you should know or be able to find on the unit circle.