English: This comes out to be -$\frac{d}{d\beta}\frac{1}{1 - e^{- \beta h\nu}}$ which is then equal to So, this is equal to Therefore, which comes out to be is equal to $\frac{h\nu}{e^{\frac{h\nu}{kT}} - 1}$ .
Telugu: ఇది -$\frac{d}{d\beta}\frac{1}{1 - e^{- \beta h\nu}}$ కు సమానం, అందువల్ల ఇది $\frac{h\nu}{e^{\frac{h\nu}{kT}} - 1}$ కు సమానం.