Whaaa! Calculating the temperature of the suns surface!

1. Nov 6, 2005

Lisa...

Hi ya all!

I'm having difficulties with estimating the temperature of the surface of the sun from a given solar spectrum. I've already determined the photon energy of the most common photons (1.15 eV). I also know that the curve of the solar spectrum (photon energy on the x-axis and intensity on the y-axis) is described with (hf^3)/((e^(hf/Kb T))-1) where the frequency f corresponding to 1 eV energy is 2.417970 x 10^14 Hz.

Now the way to retrieve the correct answer is the following:
1) Differentiate the formula.
2) Calculate the frequency of the most common photons and fill that in the formula.
3) Solve the equation where the differentiated formula (with f filled in) is set zero. (This may be done with a graphic calculator)

The only problem is that I don't seem to differentiate the formula correctly, because my calculator just can't find the points where it's zero. Could someone pleaaaaaaaaaaaaaaaaase help me to differentiate it the right way?

2. Nov 6, 2005