Question

(sin 50 degree sin 40 degree+ cos 40 degree cosec 50 degree)?EVALUATE ?

Answer 1

$\mathbb{Solution : }$


( sin50° × sin40° ) + ( cos40° × cosec50° )


=> [ sin( 90 - 40 ) × sin40° ) + ( cos40° × cosec50° )


=> ( cos40° × sin40° ) + [ cos40° × cosec( 90 - 40 ) ]


=> ( cos40° × sin40° ) + ( cos40° × sec40° )


$=> \: [ \: \: \cos(40) \sin(40)) \: \: ] + [ \: \: \: \cos(40) \times \frac{1}{ \cos(40) } \: \: \: ] \\ \\ \\ = > \sin(40) \cos(40) + 1$