更新时间2018-12-17 22:48:23
1.3sinx-根号3cosx 2.3cosx-根号三sinx 3. 2根号三sinx-2cosx 4.2cosx-2sinx 5.3sinx+4cosx
1、
3sinx - √3cosx
= 2√3·[(√3/2)·sinx - (1/2)·cosx]
= 2√3·[cos(π/6)·sinx - sin(π/6)·cosx]
= 2√3·sin[x - (π/6)]
2、
3cosx-根号三sinx
=2√3(cosx*√3/2-sinx*1/2)
=2√3(cosxcosπ/6-sinxsinπ/6)
=2√3cos(x+π/6)
3、
根号三sinx-2cosx
=4(√3/2sinx-1/2cosx)
=4(sinxcos(π/6)-cosxsin(π/6))
=4sin(x-π/6)
4、
2cosx-2sinx
=2(cosx-sinx)
=2√2(cosxcosπ/4-sinxsinπ/4)
=2√2cos(x+π/4)
5、
3sinx+4cosx
=5(-3/5sinx+4/5cosx)
=5sin(x+a) (cosa=-3/5,sina=4/5)