(sin²a-sin²b)/(sina·cosa-sinb·cosb) 如何化简,
来源:学生作业帮助网 编辑:作业帮 时间:2024/07/06 19:30:57
![(sin²a-sin²b)/(sina·cosa-sinb·cosb) 如何化简,](/uploads/image/z/5409629-53-9.jpg?t=%28sin%26%23178%3Ba-sin%26%23178%3Bb%29%2F%28sina%C2%B7cosa-sinb%C2%B7cosb%29+%E5%A6%82%E4%BD%95%E5%8C%96%E7%AE%80%2C)
(sin²a-sin²b)/(sina·cosa-sinb·cosb) 如何化简,
(sin²a-sin²b)/(sina·cosa-sinb·cosb) 如何化简,
(sin²a-sin²b)/(sina·cosa-sinb·cosb) 如何化简,
(sin²a-sin²b)/(sina·cosa-sinb·cosb) = (sin a-sin b)(sin a+sin b)/(sin(a-b)) = 2*(cos (a+b)/2)*(sin (a-b)/2)*2*(sin (a+b)/2)*(cos (a-b)/2)/(2*sin((a-b)/2)*cos((a-b)/2))=2*(cos(a+b)/2)*(sin(a+b)/2) = sin(a+b)
用到了和差化积