Question

z=arctg x/y найти производную по x

Answer 1

z'=-1/(1+x^2/y^2)*(y-xy')/y^2=(xy'-y)/(x^2+y^2)

Answer 2

частичную производную?

z'_х=1/(1+x^2/y^2)*(1/y)=y/(x^2+y^2)