$(1+\tan \theta+\sec \theta)(1+\cot \theta-\operatorname{cosec} \theta)=$
(a) 0
(b) 1
(c) 1
(d) −1
The given expression is $(1+\tan \theta+\sec \theta)(1+\cot \theta-\operatorname{cosec} \theta)$.
Simplifying the given expression, we have
$(1+\tan \theta+\sec \theta)(1+\cot \theta-\operatorname{cosec} \theta)$
$=\left(1+\frac{\sin \theta}{\cos \theta}+\frac{1}{\cos \theta}\right)\left(1+\frac{\cos \theta}{\sin \theta}-\frac{1}{\sin \theta}\right)$
$=\frac{\cos \theta+\sin \theta+1}{\cos \theta} \times \frac{\sin \theta+\cos \theta-1}{\sin \theta}$
$=\frac{(\cos \theta+\sin \theta+1)(\sin \theta+\cos \theta-1)}{\sin \theta \cos \theta}$
$=\frac{\{(\sin \theta+\cos \theta)+1\}\{(\sin \theta+\cos \theta)-1\}}{\sin \theta \cos \theta}$
$=\frac{(\sin \theta+\cos \theta)^{2}-(1)^{2}}{\sin \theta \cos \theta}$
$=\frac{\left(\sin ^{2} \theta+\cos ^{2} \theta+2 \sin \theta \cos \theta\right)-1}{\sin \theta \cos \theta}$
$=\frac{\left(\sin ^{2} \theta+\cos ^{2} \theta\right)+2 \sin \theta \cos \theta-1}{\sin \theta \cos \theta}$
$=\frac{1+2 \sin \theta \cos \theta-1}{\sin \theta \cos \theta}$
$=\frac{2 \sin \theta \cos \theta}{\sin \theta \cos \theta}$
$=2$
Disclaimer: None of the given options match with the answer.