Every positive number has a positive square root and a negative square root. Does this also apply to cube root?

Which function families have maximums and minimums? 1.)linear absolute value functions and exponential functions 2.) linear absolute value functions and quadratic functions 3.) linear absolute value functions and linear functions 4.) linear absolute value functions and constant functions

What is the standard deviation of the following data set rounded to the nearest tenth? 3, 17, 18, 15, 12, 21, 9

If value of cos330° is √3/2 then find tan165°.