Choose the correct option. Justify your choice:9 ^2A-9 ^2A= - Vidyadip

MCQ

Choose the correct option. Justify your choice:$9\sec^2\text{A}-9\tan^2\text{A}= $

A
$1$
✓
$9$
C
$8$
D
$0$

✓

Answer

Correct option: B.

$9$

$9\sec^2\text{A}-9\tan^2\text{A}$
$=9(\sec^2\text{A}-\tan^2\text{A}) $
$=9\times1=9\ [$since $ \sec^2\theta-\tan^2\theta=1] $

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