the answers don't match please help to understand

[Anya]

Hi everyone, I'm having problem with derivatives and the answer doesn't match with mine

 

[Deleted member 4993]

Hi everyone, I'm having problem with derivatives and the answer doesn't match with mine

What is the answer you should have obtained? Remember the additive constant term has a derivative of 0.

 

[Anya]

What is the answer you should have obtained? Remember the additive constant term has a derivative of 0.

thanks for your reply!
Well it's half right, why is the last additive supposed to be zero? It's because of the constant omg I was keep analyzing your message for a minute and then I finally got it.
The problem was in my inattention I learned all formulas and I accidentally used this one 1/2√x thank you very much for your help!