(sin a(1-cos a)+sina(1+ cos a)) /( 1 - )
(sin a(1-cos a)+sina(1+ cos a)) /
(1-cos a +1 +cos a)/sin a
1/sin a - ответ
(sin a(1-cos a)+sina(1+ cos a)) /( 1 -
)
(sin a(1-cos a)+sina(1+ cos a)) /
(1-cos a +1 +cos a)/sin a
1/sin a - ответ