The document you uploaded is a math problem involving a function that describes the cost development of a rental property over time. The function given is:

$f(t) = (500 + 150t + 20t^2)^{1.1}$

Where $t$ represents the number of years since the current year, and $f(t)$ represents the costs in CHF.

The task consists of three questions:

1. (3 points) Calculate the average annual increase in costs from year 1 to year 10.
2. (3 points) Find the first derivative $f'(t)$ of the function $f(t)$.
3. (3 points) Calculate $f''(2)$ and $f'(5)$, which represent the rate of change of the costs in the 2nd and 5th year.

Let's break it down:

Question 1: Average Annual Increase in Costs

To calculate the average annual increase over the period from year 1 to year 10, we need to compute the difference in the costs at $t = 1$ and $t = 10$, then divide by 9 (the total number of years between them).

Question 2: First Derivative of the Function

To find $f'(t)$, we will apply the chain rule to the given function.

Question 3: Rate of Change in Years 2 and 5

We will use the second and first derivatives $f''(t)$ and $f'(t)$ to calculate the rate of change at $t = 2$ and $t = 5$.

Would you like me to start by solving the first part or would you prefer to focus on something specific in the problem?