We will follow three steps.
We have to use the formula below because the annual interest is compounded continuously. In this formula, is the amount in the account in time is the principal, is the annual interest rate.
We know that an account pays annual interest rate compounded continuously. We want to find the number of years necessary for our principal to double. Let say the principal is equal to After years, it will double itself, Therefore,
Before we graph these functions, notice that the exponent of is so the function will grow very slowly. We may not be able to see the intersection of the lines in the standard viewing window. That's why, we should change the viewing window. We can do this by pushing
There is one point of intersection of these lines. To find this point we can use the
intersect option, which we get by pushing and Now, we select both graphs and provide the calculator with a guess as to where the intersection might be.
The solution to the equation is It would take approximately years to double our principal.