Given,
\(\frac{dx}{dt}\) = - 5 cm/min,
\(\frac{dx}{dt}\) = 4 cm/min
Let x = length, and y = breadth
Perimeter of rectangle P = 2 (x + y)
∴ Rate of change of P is
∴ Perimeter is decreasing at 2 m/s
If A be the area of rectangle then,
A = x . y
Differentiating w.r.t. 't', we get