Answer:
To find the third derivative of y = cos(2x), we'll first find the first derivative and then successively take the derivatives until we reach the third derivative.
1. First derivative (dy/dx):
y = cos(2x)
dy/dx = -2sin(2x)
2. Second derivative (d^2y/dx^2):
d(dy/dx)/dx = d(-2sin(2x))/dx
d^2y/dx^2 = -4cos(2x)
3. Third derivative (d^3y/dx^3):
d(d^2y/dx^2)/dx = d(-4cos(2x))/dx
d^3y/dx^3 = 8sin(2x)
So, the third derivative of y = cos(2x) is d^3y/dx^3 = 8sin(2x).
Explanation: