90 is 1/10 of what number?

Express the following as a function of a single angle. cos(60) cos(-20) - sin(60) sin(-20)

If $740 is invested at an interest rate of 11% per year and is compounded continuously, how much will the investment be worth in 7 years? use the continuous compound interest formula a = pert.

How to find the exponential function y=ca^x, with points (1,2) and (2,1)