Small typo in lecture 1: Einstein model

The typo can be found in the einstein model lecture:

Problematic sentence:

"There is still one step to do, rewriting this equation more elegantly: $$ C = k_b \left(\frac{T_E}{T}\right)^2\frac{e^{T_E/T}}{(e^{E_T/T} - 1)^2)}"

typo: e^{E_t/t} - 1)^2
E_T should be T_E

Correct version:

"There is still one step to do, rewriting this equation more elegantly: $$ C = k_b \left(\frac{T_E}{T}\right)^2\frac{e^{T_E/T}}{(e^{T_E/T} - 1)^2)}"