For the basic questions of advanced mathematics, please answer in detail how the green part of the answer is calculated, and the steps of writing on the blackboard should be detailed. Second adoption,
For the basic questions of advanced mathematics, please answer in detail how the green part of the answer is calculated, and the steps of writing on the blackboard should be detailed. Second adoption, please.
The first green box
( 1-x)？ = 1-2x+x？
-2x+x？ -( 1-x)？
= -2x+x？ - 1+2x-x？
= - 1
The second frame
y''=- 1 ( 1+x)^(-2)
∴y ' ' =- 1(-2)( 1+x)^(-3)
=2 ( 1+x)^(-3)