已知sin(派/4)+x=-1/5,求cos(3/4派)+x的值

来源:学生作业帮助网 编辑:六六作业网 时间:2024/06/01 07:33:02
已知sin(派/4)+x=-1/5,求cos(3/4派)+x的值已知sin(派/4)+x=-1/5,求cos(3/4派)+x的值已知sin(派/4)+x=-1/5,求cos(3/4派)+x的值cos[

已知sin(派/4)+x=-1/5,求cos(3/4派)+x的值
已知sin(派/4)+x=-1/5,求cos(3/4派)+x的值

已知sin(派/4)+x=-1/5,求cos(3/4派)+x的值
cos[(3/4派)+x]
=cos[π-(π/4-x)]
=-cos(π/4-x)
=-cos[(π/2-(π/4+x)]
=-sin(π/4+x)
=1/5