# Thread: Rate of Change

1. ## Rate of Change

A company knows that unit cost C and unit revenue R from the production and sale of x units are related by $\displaystyle C= (R^2/176,000) + 9330$. Find the rate of change of revenue per unit when the cost per unit is changing by $12 and the revenue is$4000.

2. Related rates nearly always depend on the chain rule, so you might want to try filling up this pattern... ... where straight continuous lines differentiate downwards (integrate up) with respect to the main variable (in this case x, because we're speaking of rates of change with respect to x), and the straight dashed line similarly but with respect to the dashed balloon expression (the inner function of the composite which is subject to the chain rule).

Here we're given a formula relating two variables, which is the top row... So differentiate with respect to the inner function, and the inner function with respect to x...

Spoiler: Clearly, you can now substitute the given values of R and dC/dx then solve for dR/dx.

__________________________________________
Don't integrate - balloontegrate!

Balloon Calculus; standard integrals, derivatives and methods

Balloon Calculus Drawing with LaTeX and Asymptote!

3. Originally Posted by akuczma86 A company knows that unit cost C and unit revenue R from the production and sale of x units are related by $\displaystyle C= (R^2/176,000) + 9330$. Find the rate of change of revenue per unit when the cost per unit is changing by $12 and the revenue is$4000.
$\displaystyle \frac{dC}{dt}= \frac{1}{98,000}R \frac{dR}{dt}$.

You are told that [tex]\frac{dC}{dR}= 12 and R= 4000. You can calculate C from $\displaystyle C= \frac{(4000)^2}{176000}+ 9330$ and put those numbers into the equation above.

### A company knows that the unit cost C and the unit revenue R of the production and sale of x unit are related by C=R^2/238000 2420. Find the rate of change of unit Revenue when the unit cost is changing by $9 per unit and the unit revenue is$1000

Click on a term to search for related topics.

#### Search Tags

change, rate 