I was in midst of solving a trig problem, and it required using the formula of Law of Cosine. For my case, I had to solve for a specific variable which was $\cos (A)$. Would you show me step-by-step process of how:
$$a^2 = b^2 + c^2 − 2bc\cos (A)$$
turns into
$$\cos(A)= \frac{b^2 + c^2 - a^2}{2bc}$$
$$a^2=b^2+c^2-2bc\cos(A)$$ Move $2bc\cos(A)$ to the LHS $$2bc\cos(A)+a^2=b^2+c^2$$ Move $a^2$ to the RHS $$2bc\cos(A)=b^2+c^2-a^2$$ Divide by $2bc$ on both sides $$\cos(A)=\frac{b^2+c^2-a^2}{2bc}$$