Question

Diagonal length of a square is growing at a rate of 20 meters per second. How fast is the are enclosed by the square growing at the instants the area equals 100 squared meters? Walk through please!>.<

Answer 1

related rate problem?

Answer 2

area of a square with diagonal \(x\) is \[A(x)=\frac{d^2}{2}\] is a start

Answer 3

i mean
\[A(x)=\frac{x^2}{2}\]

Answer 4

then take the derivative, get
\[A'=xx'\]

Answer 5

you are told \(x'=20\) so this gives
\[A'=20x\] then if \(x=100\) you can find \(A'\)

Answer 6

hope it is more or less clear

Answer 7

After a few tries I got it thanks(: