10.11两题

来源:学生作业帮助网 编辑:六六作业网 时间:2024/11/05 18:48:30
10.11两题10.11两题 10.11两题sin^21·+sin^22·+sin^23·+……+sin^289·=1/2(sin^21·+sin^22·+sin^23·+……+sin^28

10.11两题
10.11两题
 

10.11两题
sin^21·+sin^22·+sin^23·+……+sin^289·
=1/2 (sin^21·+sin^22·+sin^23·+……+sin^289·+sin^21·+sin^22·+sin^23·+……+sin^289·)
=1/2 【(sin^21·++sin^289)·(sin^22·+88°)+(sin^23·+87°)+……+(sin^289·+sin^21)】
=1/2 [1+1+...+1]
=1/2×89
=44.5