Question

the length of a rectangle is increasing at a rate of 8cm/s and its width is increasing at a rate of 3cm/s. When the length is 20cm and the width is 10cm, how fast is the area of the rectangle increasing? calculus question help pleasee

Answer 1

any attempt ?

Answer 2

um yeah kind of

Answer 3

will you show us your attempt ?

Answer 4

dl/dt = 8 cm/s dw/dt = 3 cm/s

A = lw

dA/dt = l*dw/dt + w*dl/dt

When l = 20 cm and w = 10 cm

dA/dt = 20(3) + 10(8)
dA/dt = 60 +80
dA/dt = ____________cm²/s