Question

Which expression is equivalent to sec²x - 1?

O A. cot²x
OB. tan²x
OC. CsC²x
OD. cos²x

Answer 1

`l = sec {}^(2) x - 1 \\ l = \frac{1}{cos {}^(2) x} - \frac{cos {}^(2) x}{cos {}^(2) x} \\ l = \frac{1 - cos {}^(2) x}{cos {}^(2)x } \\ l = \frac{sin {}^(2) x}{cos {}^(2) x} = ( (sinx)/(cosx) ) {}^(2) = tan {}^(2) x`

B