## AmTran_Bus one year ago Is there a way to get wolfram to show area of region? Trying to figure out how to use it.

1. AmTran_Bus
2. phi

Does not look promising... is this an integral problem?

3. AmTran_Bus

Well, yes and no. Here is all I know.

4. AmTran_Bus

Along with choices Area = 14.79 Area = 14.77 Area = 14.78 Area = 14.98

5. phi

then do $\int_{-4}^\infty e^{-\frac{x}{2}} \ dx$ if you know how do you know calculus?

6. AmTran_Bus

For real? Is that it? I was so overcomplicating this. I can do that.

7. AmTran_Bus

2e^2

8. phi

let u = -x/2 du = -dx/2 so dx = -2 du u goes from -(-4)/2 = 2 to u = -infinity/2 = -infinity thus $- 2 \int_2^{-\infty} e^u \ du$ or if we negate the integral we can swap the order of the integrand $2 \int_{-\infty}^2 e^u \ du = 2 e^u \bigg|_{-\infty}^2= 2e^2 - 0= 2 e^2$

9. AmTran_Bus

Phi, you are a lifesaver. Thanks a million.