cos2x/(cosx-sinx)的原函數是什麼
cos2x=cosx^2-sinx^2=(cosx-sinx)(cosx+sinx)
所以上式化簡為=cosx+sinx所以原函數為sinx-cosx
函數y=sinx•cosx•cos2x的週期
π/2
cos2x+sin2x變成√2×sin(2x+π/4) 打漏了,cos2x+sin2x變成√2×sin(2x+π/4)的過程
cos2x+sin2x
=√2(√2/2*cos2x+√2/2*sin2x)
=√2(sinπ/4*cos2x +cosnπ/4*sin2x)
=√2sin(2x+π/4)
1+sin2x+cos2x=1+sin(2x+π/4), 為什麼?
1+sin2x+cos2x
=1+√2(sin2x*√2/2+cos2x*√2/2)
=1+√2(sin2xcosπ/4+cos2xsinπ/4)
=1+√2sin(2x+π/4)
化簡f(x)=sin(2x+6/π)-sin(2x-6/π)-cos2x+1 函數f(x)=sin(2x+π/6)+sin(2x-π/6)-cos2x+1,求f(x)的最小正週期、對稱軸、對稱中心、單調增區間。
6/π?通常是π/6啊,下麵我當π/6來解吧:
f(x)=sin(2x+π/6)-sin(2x-π/6)-cos2x+1
=(sin2xcosπ/6+cos2xsinπ/6)-(sin2xcosπ/6-cos2xsinπ/6)-cos2x+1
=2cos2xsinπ/6-cos2x+1
=cos2x-cos2x+1
=1
[1+cos2X+sin^2x]/sinx怎麼化簡?
cos2x =(cosx)^2 -(sinx)^2 =1-2(sinx)^2
帶入得到2-(sinx)^2/sinx = 2/sinx - sinx
化簡cos2x/(cosxsinx-sin^2x) 第一個是cos2x,最後一個是sin的平方x.別搞混了.
cos2x/(cosxsinx-sin^2x)
=(cosxcosx-sinxsinx)/[(cosx-sinx)sinx]
=(cosx+sinx)/sinx
=1+1/tanx
(1+cos2x)/2cosx=sin2x/(1-cos2x)
已知sin2x=2sinxcosx cos2x=(cosx)^2-(sinx)^2所以1-cos2x=2(sinx)^21+cos2x=2(cosx)^2所以(1+cos2x)/2cosx=sin2x/(1-cos2x)化解為2(cosx)^/2cosx=2sinxcosx/2(sinx)^2cosx=cosx/sinxsinx=1x=arcsin1如果要數位…
若tanx等於√2,則(cos²x-cos2x)/1-sin²x=____?
(cos²x-cos2x)/1-sin²x =[cos²x-(2cos²x-1)]/cos²x=(1-cos²x)/cos²x =tan²x =2
求函數y=sin(60-2x)+cos2x的週期
y=sin(60-2x)+cos2x
=sin60cos2x-cos60sin2x+cos2x
=(1+根號3)/2*cos2x-1/2*sin2x
=根號下[((1+根號3)/2)^2+(-1/2)^2]*sin(2x+w)
所以週期為2π/2=π