Penny works at a localamusement park.
She earns $9.80 per hour.
She is also paid $7.00 for
meals and $3.00 for
transportation each day.
Last Friday, Penny earned
$88.40. Write and solve an
equation to determine how
many hours Penny worked
on Friday.

To find the instantaneous rate of change of the function f(x,y) = x^2 + ln(y) at (3,1) to (1,2), we can use the partial derivatives with respect to x and y:

fx(x,y) = 2x

fy(x,y) = 1/y

Then, we can use the gradient vector to find the direction of maximum increase:

∇f(x,y) = <fx(x,y), fy(x,y)> = <2x, 1/y>

At point (3,1), the gradient vector is:

∇f(3,1) = <6, 1>

At point (1,2), the gradient vector is:

∇f(1,2) = <2, 1/2>

To find the instantaneous rate of change from (3,1) to (1,2), we can use the formula for directional derivative:

Dv(f) = ∇f(x,y) · v

where v is the unit vector in the direction from (3,1) to (1,2). The direction vector v is given by:

v = <1, 2> - <3, 1> = <-2, 1>

To make v a unit vector, we need to normalize it by dividing it by its length:

|v| = sqrt((-2)^2 + 1^2) = sqrt(5)

u = v/|v| = <-2/sqrt(5), 1/sqrt(5)>

Then, the instantaneous rate of change from (3,1) to (1,2) is:

Dv(f) = ∇f(3,1) · u = <6, 1> · <-2/sqrt(5), 1/sqrt(5)> = (-12/sqrt(5)) + (1/sqrt(5)) = -11/sqrt(5)

Therefore, the instantaneous rate of change of the function f(x,y) = x^2 + ln(y) from (3,1) to (1,2) is -11/sqrt(5).

To learn more about instantaneous rate of change refer below:

brainly.com/question/31011769

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