Hi! My friend asked me to help to check if the derrivative of equation 9 is like equation 10. I don't really how to solve it manually so I try to check from a couple of app and use software, but the result is different. Can you help me to check and explain if the derrivative is actually correct.
I try with wolfram mathematica web :
wolfram mathematica software :
I also try to use derrivative calculator on internet (i change theta to x in this app) :