Find Y' when Y= X^(2)e^(cos2x)
These are the steps my teacher wrote down on the board. She used the Product rule.
a) Y'= [{X^(2)}' *{e^(cos2x)}] + [{X^(2)} *{e^(cos2x)}']
b) Y' = 2Xe^(cos2x) + X^(2)e^(cos2x) * [1-2sin(2x)]
c) Y' = 2Xe^(cos2x)[1-2sin(2x)]
So my questions are.
1) Where did that 1 come from?
2) How to go from step b to step c. Especifically why did X^(2)e^(cos2x) disapear in the final answer.