The peak value of this curve, as determined by setting the derivative of the equation equal to zero and solving, occurs at a wavelength λ λ max = h c 5 k B T ≈ ≈ 0.2878 c m ⋅ ⋅ K T , and frequency ν ν max = 3 k B T h ≈ ≈ 6.25 × × 10 10 H z K ⋅ ⋅ T .