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**HELP!!!A problem on resistivity**

**1. The problem statement, all variables and given/known data**

For some application it is important that the value of a resistance not change with temperature. For example, suppose you made a 3.70 KΩ resistor from a carbon resistor and a Nichrome wire-wound resistor connected together so the total resistance is the sum of their separate resistances. What value should each of these resistors have (at zero degree celsius) so that the combination is temperature independent

**3. The attempt at a solution**

Resistivity of carbon resistor, ρ: 3~60*10^-5

Resistivity of Nichrome resistor, ρ: 100*10^-8

ρ=ρo[1+α(T-To)]

But resistance is R=ρ*(l/A)

I can write the equation like

R=Ro[1+α(T-To)]

However, the question doesn’t have length and area of the resistor, otherwise I can use that to solve for Ro, so I don’t really know how to continue on with the problem.

Any help would be great. Thank you very much