Question

find the value of cosec(-990)​

Answer 1

Answer:

cosec(-990)= cosec(2*360+270)

= cosec(-270)= sin(1/-270) = -1.

Answer 2

$\underline \bold{ \large{Solution \: \: \: \: }}$

$\to \: \bold{ \: Cosec \: ( - 990 )} \\ \\ \to\bold{- Cosec \: ( 990 ) \: } \\ \\ \to \bold{- Cosec \: ( 360 × 3 - 90 ) \: } \\ \\ \to \bold{- \: (- Cosec \: ( 90 )) \: } \\ \\ \to \bold{ \: \: Cosec \: ( 90 ) \: } \\ \\ \to \bold{ \: \: \: \: \: \: \: 1}$

$\underline \bold{ \large{Identity \: Used \: \: \: \: }}$

• Cosec (-Theta) = - Cosec (Theta)

• Cosec (360 × n - Theta) = -Cosec (Theta)