A spring oscillates with a frequency of 3.5 cycles per second. Its initial displacement is 15 centimeters and it's damping factor is 0.25. Give the function, `f(t)` that describes the position of the spring `t` seconds after it starts oscillating.

Box 1: Enter your answer as an equation. Example: y=3x^2+1, 2+x+y=3
Be sure your variables match those in the question