I have a ClassPad 300+ but I'm having trouble using the solver to find variables inside the integral:

I used the emulator to take a screenshot (emulator is on version 2.2), but I currently have 3.06 installed (which hides the integration variable automatically-the lamda symbol). The error message I get is "Undefined Variable" when solving for T. I should add that I can solve for E on the actual calculator, which gives an answer of ~1366, so E is normally set first before I try to solve T. The reason it is 0 here is the emulator couldn't deal with this problem at all.

It's odd though, since someone else pointed out that you can solve for variables inside an integral with simpler integrals, but for some unexplicable reason, this one won't work.

Variables:

h = Planck's constant

c = Speed of light (m/s)

r = Sun's Radius (m)

D = Earth's Distance (1AU)

k = Boltzman constant

T = Sun's Temperature (Kelvin)

E = Solar Irradiance (W/m^2)

Lambda = wavelength (m)

This is no problem for my fx-CG50/fx-9750GII or even my fx-991EX, but I can't see how it can done on the Classpad.

Any help is much appreciated!

**Edited by MJim, 04 March 2021 - 12:35 AM.**