In $ riangleABC$ if $\beta=90^{\circ}$, then according to law of cosine the value of the square of the side b is defined as:

Question

Accepted Answer

$b^{2}=a^{2}+c^{2}$

Answer

$b^{2}=a^{2}+b^{2}-2ab$

Answer

$b^{2}=b^{2}+b^{2}-2bc\cos\beta$

Answer

$b^{2}=a^{2}+c^{2}+2ac\cos\beta$