# Determine the current

• February 19th 2009, 08:28 AM
Stazzer5
Determine the current
The power developed in a circuit is given by P = 10I-8I^2 where I is the current in amps. determine the current required to produce a power of 1.75 watts in th circuit.

Many thanks.
• February 19th 2009, 10:22 AM
running-gag
Hi

You need to solve $10I-8I^2=1.75$ which is a second degree polynomial equation.
Do you know how to solve this type of equation ?
• February 19th 2009, 11:58 AM
Stazzer5
hi there,

Thank you for your help. I dont know how to work this out.

Thanks again

thanks
• February 20th 2009, 01:09 AM
mr fantastic
Quote:

Originally Posted by running-gag
Hi

You need to solve $10I-8I^2=1.75$ which is a second degree polynomial equation.
Do you know how to solve this type of equation ?

Quote:

Originally Posted by Stazzer5
hi there,

Thank you for your help. I dont know how to work this out.

Thanks again

Re-arrange: $8 I^2 - 10 I + 1.75 = 0$.