Question

The value of the expression $({\tan }^{2}x+1)({\cos }^{2}x+1)-{\tan }^{2}x$ is

Answer 1

$({\tan }^{2}x+1)({\cos }^{2}x+1)-{\tan }^{2}x={\sin }^{2}x+{\tan }^{2}x+{\cos }^{2}x+1-{\tan }^{2}x=2$