E
Editor
Sep 18, 2022
In $\triangleABC$ if$\alpha=90^{\circ}$ then according to law of cosine the value of the square of the side a is defined as
Difficulty: Easy
A:
$a^{2}=b^{2}+c^{2}$
B:
$a^{2}=a^{2}+c^{2}+2ac$
C:
$a^{2}=b^{2}+c^{2}+2bc\cos\alpha$
D:
$a^{2}=b^{2}+c^{2}-2bc\cos\alpha$
ID: 63273db9ca83163ac3a119af