Of course it is a good exercise to calculate derivatives by first principles , but often , this is not elegant . Many derivatves can be derived from the product rule which should be taught at the beginning . Example : (1/√x )' : set y[x]= 1/√x . Then y[x]^2* x = 1 . By the product rule and taking the derivative on both sides we have 2 y[x]* y ' [x] *x + y[x]^2 = 0 ,from which it follows that y ' [x]= - 1/2 *y[x]/x = -1/2*x^(-3/2) .
@iqinitiative11 ай бұрын
Yes but some questions are usually specific on using the 1st Principle