Homework Help: calculus - please help!

Posted by archi on Monday, November 7, 2011 at 6:07pm.

If two resistors R1 and R2 are connected in parallel, then the total resistance R measured in ohms is given by

1/R=1/R1+1/R2

If the resistance of R1 and R2 are increasing at 330 and 660 ohms per second respectively, then the rate of increase of R when R1=5000 and R2=5000 is how many ohms per second?

calculus - please help! - Steve, Monday, November 7, 2011 at 8:06pm
Just plug and chug

1/R = 1/R1 + 1/R2
1/R = 1/5000 + 1/5000 = 2/5000
R = 2500

-1/R^2 R' = -1/R1^2 R1' - 1/R2^2 R2'
-1/625E4 R' = -1/25E6 * 330 - 1/25E6 * 660
1/625E4 R' = 990/25E6
R' = 990*625E4/25E6 = 990*625/2500
R' = 247.5 ω/s

Answer this Question

Related Questions

PreCalc - The total electrical resistance R of two resistors connected in ...
Pre-Calc - Hello, I am not sure how to go about solving this equation: The total...
Algebra - Simplify rt= 1/[(1/r1)+ (1/r2)] That looks like the formula for the &...
Electricity and Electronics - A circuit contains twodevices that are connected ...
physics: Electricity/Resistance - If I have a 9V circuit, with: 2 resistors in ...
maths - if two resistors of r1 and r2 ohms are connected in parallel in an ...
Physics - Consider the circuit shown in the figure below. Use the following as ...
physics - Resistors R1, R2, and R3 have resistances of 15.0 Ohms, 9.0 Ohms and 8...
physics (please check) - A total resistance of 3 ohms is to be producd by ...
Physics URGENT - I did a lab on DC circuits, and we calculated the resistance of...

For Further Reading

First Name:
School Subject:
Answer: