यदि `sec alpha=13/5` जहाँ ` 270^(@)lt alpha lt 360^(@)` है , तो ` sin alpha` किसके बराबर है ?

Options

A. `5//13`
B. `12//13`
C. `-12//13`
D. `-13//12`

Answer

c

Explanation

` :. sec alpha = 13/5 rArr cos alpha = 5/13`
` rArr sin alpha = sqrt(1 - cos^(2) alpha )= sqrt(1-25/169)`
` = sqrt(144/169) = - 12/13`
` ["चूँकि " sin alpha , 270 ^(@) lt alpha lt 360 ^(@)` में
ऋणात्मक होता है ।