Question

In the lecture 1 of Calculus I, near the end the professor states that 2*(x sub zero * y sub zero) = 2 as if (x sub zero * y sub zero) were equal 1. Why?

Answer 1

because in the original equation \[y=1/x\] if you multiple everything by x you will get \[x*y=1\]
so for any value of x multiplied by y the answer will always be 1.

Answer 2

This is great. Thanks

Answer 3

Which lecture you are refering to.