# Is the following math operation allowed?

#### bluesky44

Is the following allowed:

$$\displaystyle (x-1)^\frac{1}{2}(x+1)^\frac{1}{2}=\sqrt{x^2-1}$$

#### Plato

MHF Helper
Is the following allowed: $$\displaystyle (x-1)^\frac{1}{2}(x+1)^\frac{1}{2}=\sqrt{x^2-1}$$
The short answer is yes, provided one takes special care with domain issues.
It is certainly value for $$\displaystyle x\ge 1$$.