45 minutes as you only have to divide 60 by 4 and then multiply it times 3
Let
![I = \displaystyle \int e^{-2x} \cos(2x) \, dx[/]texIntegrate by parts:[tex]\displaystyle \int u \, dv = uv - \int v \, du](https://tex.z-dn.net/?f=I%20%3D%20%5Cdisplaystyle%20%5Cint%20e%5E%7B-2x%7D%20%5Ccos%282x%29%20%5C%2C%20dx%5B%2F%5Dtex%3C%2Fp%3E%3Cp%3EIntegrate%20by%20parts%3A%3C%2Fp%3E%3Cp%3E%5Btex%5D%5Cdisplaystyle%20%5Cint%20u%20%5C%2C%20dv%20%3D%20uv%20-%20%5Cint%20v%20%5C%2C%20du)
with

Then

Integrate by parts again, this time with

so that

B. r = 75m + 1350 I think is the answer. I hope this helped you!
The answer would be F. Multiply 64,000 by 0.07 (that decimal representing 7%) to get 4,480