How do I express this equation as a monomial with i?

How do you use the additive inverse to evaluate an expression that uses subtraction in a full sentence

Describe in detail how you would construct a 95% confidence interval for a set of 30 data points whose mean is 20 and population standard deviation is 3. be sure to show that you know the formula and how to plug into it. also, clearly state the margin of error.

Write the expression as a constant , a single trigonometric function, or a power of a trigonometric function. sin x cos x/ tan x