Question

If y= cos(1-x) find dy by dx

Answer 1

Let t = 1-x

dt/dx = -1

dy/dx = dy/dt * dt/dx

y = cos (1-x)

​​​​​​t = 1-x

y = cos t

dy/dt = - sint

dy/dx = dy/dt * dt/dx

dy/dx = - sint * (-1)

dy/dx = sint

dy/dx = sin(1-x)

Answer : dy/dx = sin(1-x)