the width of a rectangle is increasing at a rate of 5 inches per second and its length is increasing at the…

the width of a rectangle is increasing at a rate of 5 inches per second and its length is increasing at the rate of 3 inches per second. at what rate is the area of the rectangle increasing when its width is 2 inches and its length is 7 inches? (hint: let (w(t)) and (l(t)) be the width and length, respectively, at time (t).) the rate that the area of the rectangle is increasing is (square) in²/s. (simplify your answer.)
Answer
Explanation:
Step1: Recall area formula
Let $w$ be the width and $l$ be the length of the rectangle. The area $A = wl$.
Step2: Differentiate with respect to time
Using the product - rule $\frac{dA}{dt}=l\frac{dw}{dt}+w\frac{dl}{dt}$.
Step3: Identify given values
We know that $\frac{dw}{dt}=5$ inches per second, $\frac{dl}{dt}=3$ inches per second, $w = 2$ inches and $l = 7$ inches.
Step4: Substitute values
$\frac{dA}{dt}=(7\times5)+(2\times3)$.
Step5: Calculate result
$\frac{dA}{dt}=35 + 6=41$.
Answer:
$41$