# Question #dce15

Dec 22, 2015

This identity is false, AKA not an identity.

#### Explanation:

To show that an equation isn't true, all you need is a counterexample.

Assume that $\alpha = \beta = \frac{\pi}{6}$.

The left-hand side of the equation evaluates to $2$. However, the right-hand side evaluates to $\frac{2 \sqrt{3}}{3}$. Since it doesn't hold for these particular values of $\alpha$ and $\beta$ it's reasonable to say that this equation is false in general.

Did you possibly make a typo? Typically if you're asked to prove something, it's actually true.