# GRE Practice Question

Let k be the number of real solutions of the equation e$$^{x}$$ + x - 2 = 0 in the interval [0,1] and let n be the number of real solutions that are not in the interval.

By looking at the graph, I know it crosses the x axis; however, I don't remember or know how to do this problem.

LCKurtz
Homework Helper
Gold Member
Hint: If f(x) = ex + x - 2, look at f(0), f(1) and f '(x).

I know what f(0) and f(1) are and f '(x) = e$$^{x}$$ + 1

How is that suppose to help?

LCKurtz
Homework Helper
Gold Member
I know what f(0) and f(1) are and f '(x) = e$$^{x}$$ + 1

How is that suppose to help?

You mean "supposed" to help.

What does the fact that f(0) and f(1) have opposite signs tell you? What does having a positive derivative tell you? And, of course, I'm just assuming I know what your actual question was since your original post doesn't actually contain a question.

At least this isn't an English forum. The question was in regards to multiple choices so I left that out because it wasn't needed.

LCKurtz