使f(x)=sinx+cosx=√2*sin(x+π/4) 步骤是什么f(x)=sinx+cosx=√2(√2/2sinx+√2/2cosx) -------(提一个√2出来) =√2(sinxcosπ/4+cosxsinπ/4)-(把(√2/2分别变为cosπ/4,sinπ/4) =√2*sin(x+π/4) --------

来源:学生作业帮助网 编辑:作业帮 时间:2024/05/07 03:20:56
使f(x)=sinx+cosx=√2*sin(x+π/4) 步骤是什么f(x)=sinx+cosx=√2(√2/2sinx+√2/2cosx) -------(提一个√2出来)    =√2(sinxcosπ/4+cosxsinπ/4)-(把(√2/2分别变为cosπ/4,sinπ/4)    =√2*sin(x+π/4)            --------

使f(x)=sinx+cosx=√2*sin(x+π/4) 步骤是什么f(x)=sinx+cosx=√2(√2/2sinx+√2/2cosx) -------(提一个√2出来) =√2(sinxcosπ/4+cosxsinπ/4)-(把(√2/2分别变为cosπ/4,sinπ/4) =√2*sin(x+π/4) --------
使f(x)=sinx+cosx=√2*sin(x+π/4) 步骤是什么
f(x)=sinx+cosx=√2(√2/2sinx+√2/2cosx) -------(提一个√2出来)
=√2(sinxcosπ/4+cosxsinπ/4)-(把(√2/2分别变为cosπ/4,sinπ/4)
=√2*sin(x+π/4) ------------------ (两角和正弦公式)
这里有一个,看不懂,特别是到了最后一步不懂了

使f(x)=sinx+cosx=√2*sin(x+π/4) 步骤是什么f(x)=sinx+cosx=√2(√2/2sinx+√2/2cosx) -------(提一个√2出来) =√2(sinxcosπ/4+cosxsinπ/4)-(把(√2/2分别变为cosπ/4,sinπ/4) =√2*sin(x+π/4) --------
和差化积公式.sin(x+y)=sinx*cosy+cosx*siny

sin(x+y)=sinx*xosy+cosy*sinx