1. The problem statement, all variables and given/known data At what wavelength is u(lambda) a maximum for a star with a surface temperature of 50,000 K? 2. Relevant equations Planck's law u(lambda)=8(pi)hc/(lambda^5*(e^(hc/kTlambda)-1) 3. The attempt at a solution I think the maximum is where the derivative of the function u(lambda)=0, but the derivative is too messy to solve in terms of lambda so I can't find the wavelength. So I think I'm way off as far as how to solve it. Any help would be appreciated.