could you please help me to solve this problem please. Thank you.
Several approaches are possible.
There's a simple one if you know differential calculus ..... you can consider the function . Then, with a (perhaps disquieting) change from the usual notation ( instead of , instead of ) you can consider the derivative of from first principles:
.
So the answer will be the derivative of f(a) with respect to a ....
I agree. I'm helping someone right now.
But substituting the math and typing tex at the same is tough for me.
I'm afraid I'll do a stupid calculation and I cannot edit after 15 minutes.
Leaving forever with a dumb math error.
That would be embarassing.
I really like the conjugate technique.