Question

Помогите решить!!!!!!!!!!!!!

Answer 1

$u=sin^2(x-4y)\\dfrac{partial u}{partial x}=2, sin(x-4y)cdot cos(x-y)=sin(2x-8y)\\dfrac{partial u}{partial y}=2, sin(x-4y)cdot cos(x-4y)cdot (-4)=-4, sin(2x-8y)\\dfrac{partial ^2u}{partial x^2}=cos(2x-8y)cdot 2=2, cos(2x-8y)\\dfrac{partial ^2u}{partial y^2}=-4, cos(2x-8y)cdot (-8)=32, cos(2x-8y)\\\16cdot dfrac{partial ^2u}{partial x^2}=16cdot 2, cos(2x-8y)=32, cos(2x-8y)=dfrac{partial ^2u}{partial y^2}$

Answer 2

есть таблица производных и правила дифференцирования...