If the function y

If the function y = .014 t² + -1.3 t + 85 represents depth y vs. clock time t, then what is the average rate of depth change between clock times t = 12.1 and t = 24.2?

What is the rate of depth change at the clock time halfway between t = 12.1 and t = 24.2?

What function represents the rate r of depth change at clock time t?

What is the value of this function at the clock time halfway between t = 12.1 and t = 24.2?

If the rate of depth change is given by dy/dt = .168 t + -1.4 represents the rate at which depth is changing at clock time t, then how much depth change will there be between clock times t = 12.1 and t = 24.2?

Give the function that represents the depth. What would this specific function be if at clock time t = 0 the depth is 100?