Question

how do i prove that x^2 - 2 = 0 has a solution in the positive real numbers?

Answer 1

x^2 - 2 = 0 add 2 to both sides
x^2 = 2 square root both sides
x = +-sqrt(2) plus or minus sqrt(2)
x = +1.4142

Answer 2

how do i prove that sqrt(2) is in the positive reals?

Answer 3

It's got a plus sign... makes it positive.
It doesn't have an "i" so it is real.

Answer 4

thank you!