Exercise

# Forecasting over time

In this exercise, you're going to use NumPy arrays to explore how an investment increases over 20 years. The forecast is calculated using the following formula:

\( balance = deposit (1 + rate)^{years} \)

You need to calculate and plot the percent gain on the investment for each month over 20 years, which is represented by the NumPy array `years`

and has already been loaded into your workspace, along with the `deposit`

and `annual_rate`

of return. The calculation for percent gain is as follows:

\( gain = \dfrac{(balance-deposit)}{deposit}\times100\)

Instructions

**100 XP**

- Forecast the balance in the account for each time point in the variable
`years`

. - Calculate the percent gain in the account.
- Plot the percent gain as a function of years.