(U*V)'=U'V+UV'; (√Х)'=1/(2√X); (ARCTGU)'=(1/(1+U²))*U'
(√x*arctg(1/x))'=(arctg(1/x))/(2√x)+√x*(1/(1+(1/x)²)*(-1/x²)=
(arctg(1/x))/(2√x)-√x*(1/(1+x²)
(U*V)'=U'V+UV'; (√Х)'=1/(2√X); (ARCTGU)'=(1/(1+U²))*U'
(√x*arctg(1/x))'=(arctg(1/x))/(2√x)+√x*(1/(1+(1/x)²)*(-1/x²)=
(arctg(1/x))/(2√x)-√x*(1/(1+x²)