Question

Getting another Calculator Error Cosine Law Trig

Here is the problem

A = 103 degrees
Sides are
b =31
c=52

Equation
\( a^2 = 31^2+52^2-2\times 31 \times 52 \) = a = 66.2589
\( \large \cos B = \frac{66.25^2 +52^2-31^2}{2\times 66.25\times52}\)

Am I right so far?? Do you get an error?