Question

If y = cos nx, then `(d^2y)/dx^2 + n^2y` = ______ 

विकल्प

• 1

• -m² 

• 0

• -1

Answer 1

If y = cos nx, then `(d^2y)/dx^2 + n^2y` = 0

Explanation:

y = cos nx .........(i)

∴ `dy/dx` = -n sin nx

∴ `(d^2y)/dx^2 = -n^2 cos nx`

⇒ `(d^2y)/dx^2 + n^2y = 0` ..........[From (i)]