Trigonometric Identities Question 369

Question: If $ A+B=\frac{\pi }{4}, $ then $ (1+\tan A)(1+\tan B)= $

Options:

A) 1

B) 2

C) $ \infty $

D) -2

Show Answer

Answer:

Correct Answer: B

Solution:

Given that $ A+B=\frac{\pi }{4},\Rightarrow ,\tan ,(A+B)=\tan ,\frac{\pi }{4} $
$ \Rightarrow \frac{\tan A+\tan B}{1-\tan A,\tan B}=1 $
$ \Rightarrow \tan A+\tan B+\tan A,\tan B=1 $
$ \Rightarrow (1+\tan A),(1+\tan B)=2 $ .