Hello, m777!
1) Prove that the derivative of . .is: .
Multiply first: .
And we have: .
Then: .
Multiply "top and bottom" by
Therefore: .
3) Differentiate: .
Square first: .
So we have: .
Then: .
Therefore: .
2) Differentiate: .
I'm still working on this one, but I would "rationalize" first.
Multiply top and bottom by
. .
. .
. . . . . then differentiate.
. . . . . ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
I don't agree with the given answer.
. . (Why aren't the 2's cancelled out?)
Could it be: . ?