Question

follow these steps to derive the law of cosines. 1. the relationship between the side lengths in △abd is c² = x² + h² by the pythagorean theorem. lengths in △cbd is an theorem. equation a² = b² - 2bx + x² + h² becomes a² = b² - 2bx + c² by

Explanation:

Step1: Recall the given equations

We have $c^{2}=x^{2}+h^{2}$ and $a^{2}=b^{2}-2bx + x^{2}+h^{2}$.

Step2: Substitute $c^{2}$

Since $c^{2}=x^{2}+h^{2}$, we substitute $x^{2}+h^{2}$ with $c^{2}$ in the second - equation.

Answer:

substitution