the-resistance-of-a-conductor-is-5-ohm-at-50-c-and-6-ohm-at-100-c-its-resistance
Well, try thinking about it this way: the resistance changed by only ##1 Omega## over ##50^oC##, which is a pretty large temperature range. So, I would say it’s safe to assume the change in resistance with respect to temperature (##(DeltaOmega)/(DeltaT)##) is pretty much linear.
##(DeltaOmega)/(DeltaT) ~~ (1 Omega)/(50^oC)##
##DeltaOmega = (1 Omega)/(100^oC-50^oC)*(0^oC-50^oC) ~~ -1 Omega##
##Omega_(0^oC) ~~ 4 Omega##
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