Which function has a range of (−90°, 90°)?

  C)  f(x) = tan^-1(x)

Step-by-step explanation:

The question is equivalent to asking which trig function passes the horizontal line test over the domain (-90°, 90°). Both the sine function and the tangent function are defined on that domain and pass the horizontal line test.

The inverse sine function has a range of [-90°, 90°] (with square brackets, signifying the end points are part of the range). The inverse tangent function does not have a range that includes ±90°, so is a better match for the range in the question.

x = 12.5

Step-by-step explanation:

By Pythagoras'

16² = 10² + x²

x² = 16² - 10²

x = √(16² - 10²)

x = 12.489...

x = 12.5 (nearest tenth)