Question

$(\sec A-\cos A)(\sec A+\cos A)={\sin }^{2}A+{\tan }^{2}A$.

• A. True
• B. False

Answer 1

The correct option is A True

$(\sec A-\cos A)(\sec A+\cos A)$

$={\sec }^{2}A-{\cos }^{2}A$

$=1+{\tan }^{2}A-{\cos }^{2}A$

$=1-{\cos }^{2}A+{\tan }^{2}A$

$={\sin }^{2}A+{\tan }^{2}A$