Question

15.If the side of the square are decreasing at the rate of 1.5 cm/sec , then
at what rate is the perimeter decreasing
5 cm/sec
4 cm/sec
O 6 cm/sec
O 2 cm/sec​

Answer 1

$length \: of \: square \times 4 = perimeter \\ \\ \\hance \: rate \: of \: change \: of \: perimeter \\ 1.5 \times 4 = 6$

unit is cm/sec

Answer 2

Answer:

If x cm. is the side of the square and p cm. is the perimeter.

p=4x

∴

dt

dp

=4

dt

dx

=4×0.5 (∵

dt

dx

=0.5 given)

=2

∴ The perimeter is increasing at the rate of 2 cm/sec.