Дана функция двух переменных. Найти первые и вторые частные производные

Dzdx=x4+yx2+y3x'=12x4+yx2+y3*x4+yx2+y3x'=4x3+2xy2x4+yx2+y3=2x3+xyx4+yx2+y3
dzdy=x4+yx2+y3y'=12x4+yx2+y3*x4+yx2+y3y'=x2+3y22x4+yx2+y3
d2zdx2=2x3+xyx4+yx2+y3x'=2x3+xyx'x4+yx2+y3-2x3+xyx4+yx2+y3'x4+yx2+y32=6x2+yx4+yx2+y3-2x3+xy*2x3+xyx4+yx2+y3x4+yx2+y32=6x2+yx4+yx2+y3-2x3+xy*2x3+xyx4+yx2+y33=6x6+7x4y+6x2y3+x2y2+y4-4x6-4x4y-x2y2x4+yx2+y33=2x6+3x4y+6x2y3+y4x4+yx2+y33
d2zdy2=x2+3y22x4+yx2+y3y'=x2+3y2y'2x4+yx2+y3-x2+3y22x4+yx2+y3y'2x4+yx2+y32=6y*2x4+yx2+y3-x2+3y2*2*x2+3y22x4+yx2+y32x4+yx2+y32=6y*2x4+yx2+y3-x2+3y2*x2+3y2x4+yx2+y32x4+yx2+y32=12x4y-x4+6x2y2+3y44x4+yx2+y33
d2zdxdy=2x3+xyx4+yx2+y3y'=2x3+xyy'x4+yx2+y3-2x3+xyx4+yx2+y3y'x4+yx2+y32=x*x4+yx2+y3-2x3+xy*x2+3y22x4+yx2+y3x4+yx2+y32=2x5+2x3y+2xy3-2x5-6x3y2-x3y-3xy32x4+yx2+y33=x3y-xy3-6x3y22x4+yx2+y33