Question

Calculus II: Can someone explain to me where the standalone 2s in the numerator on the last line came from?

Answer 1

yes

Answer 2

square
the middle terms will be \(2e^{-1+1}=2e^0=2\)

Answer 3

just like \[\left(\frac{1}{x}+x\right)^2=\frac{1}{x^2}+2+x^2\]