standard_description: Choose trigonometric functions to model periodic phenomena with specified amplitude, frequency, and midline.
problem_activity: Task
Given a function $f$, is the statement $$f(x+h)=f(x)+f(h)$$ true for any two numbers $x$ and $h$? If so, prove it. If not, find a function for which the statement is true and a function for which the statement is false.


aligns: no