Найти dydx иd2ydx2 для заданных функций

А) y=x-arcsinx
dydx=x-arcsinx'=x'-arcsinx'=12x-11-x2;
d2ydx2=12x-11-x2'=12x-12'-1-x2-12'=
=12∙-12∙x-12-1--12∙1-x2-12-1∙1-x2'=
=-14∙x-32+12∙1-x2-32∙0-2x=-14∙x-32-x∙1-x2-32.
б) x=arctg t2; y=12t+1t.
Функция задана параметрически.
y' x=y' tx' t.
x't=arctg t2=11+t22 ∙t2'=2t1+t4;
y't=12t+1t'=-12t+1t-1'=12∙-1t+1t-1-1∙t+t-1'=
=-12∙t+1t-2∙1+-1∙t-1-1=-12∙t+1t-2∙1-1t2=
=-12∙t2-1t2+12.
y' x=-12∙t2-1t2+12:2t1+t4=-t2-11+t44tt2+12.
y'' xx=y' x' tx' t.
y'x' t=-t2-11+t44tt2+12'=-t6+t2-t4-14tt2+12'=
=-14∙t6+t2-t4-1'∙tt2+12-tt2+12'∙t6+t2-t4-1tt2+122=
=-14∙6t5+2t-4t3∙tt2+12-t2+12+2tt2+12t∙t6+t2-t4-1tt2+122
=-14∙6t5+2t-4t3∙t3+t-5t2+1∙t6+t2-t4-1t2t2+13=
=-6t8+2t4-4t6+6t6+2t2-4t4-5t8-5t4+5t6+5t2-t6-t2+t4+14t2t2+13=
=-t8+6t6-6t4+6t2+14t2t2+13
y'' xx=-t8+6t6-6t4+6t2+14t2t2+13:2t1+t4=-t8+6t6-6t4+6t2+11+t48t3t2+13.