Verify that `y=A cos x-B sin x ` is a solution of the differential equation `(d^(2)y)/(dx^(2))+y=0`

What is the degree of the differential equation (d^(2)y)/(dx^(2))=1+((dy)/(dx))^(1//2)?

Write the order and degree of the differential equation x^(2)((d^(2)y)/(dx^(2)))^(1//2)=(dy)/(dx)

Answer the following questions: Find the order and degree of the differential equation (d^2y)/(dx^2)-7((dy)/(dx))^3+6y=0