\magnification=\magstep2

$$
   \lambda_{\rm peak} = { { 0.290 {\rm \ cm\ K}  } \over { T } }
$$

$$
   L =  4 \pi R^2 \sigma T^4
$$

$$
   L = A \sigma T^4
$$

$$
   B_\lambda(T) =   { { 2 h c^2 / {\lambda}^5 } \over 
                        { e^{h c / \lambda k T} - 1 }  }
$$


$$
   B_{\nu} (T) = { { 2 h {\nu}^3 / c^2 } \over 
                       { e^{h \nu / k T} - 1 } }
$$


$$
   F = \int_{\lambda_1}^{\lambda_2} { B_\lambda(T) d\lambda }
     = \int_{\nu_1}^{\nu_2} { B_\nu(T) d\nu }
$$

$$
    \int_{\lambda_0 - \epsilon}^{\lambda_0 + \epsilon} { B\lambda(T, \lambda) d\lambda } 
       \simeq  B_\lambda(T, \lambda_0) \{ (\lambda_0 + \epsilon) -
                                             (\lambda_0 + \epsilon) \}
$$


$$
     \quad \simeq   B_\lambda(T, \lambda_0) \{  2 \epsilon  \}
$$

\bye
