8cos(100t 60)

解化简(1-cos²α)/(sinα-cosα)-(sinα+cosα)/(tan^2α-1)=sin²α/(sinα-cosα)-(sinα+cosα)/(sin²a/

cos(5/根号41)最好画一个三角形,由tan0.8,得两直角边,一边为4一边为5,得斜边为根号41,求出cos

cos5π/8*cosπ/8=-cos(π-5π/8)*cosπ/8=-cos3π/8*cosπ/8=-cos(π/2-π/8)*cosπ/8=-sin(π/8)*cosπ/8=-sin(π/4)/2

就是cosername的缩写,是coser们在cosplay圈里用的名字,这货就是一个coser哟,CN是白清明

解由（cosα-sinα）²=cos²a-2sinαcosα+sin²a=1-2sinαcosα=1-2×1/8=3/4即cosα-sinα=±√3/2.

d/dxsin^8(cos(4x))=8sin^7(cos(4x)dsin(cos(4x)/dx=8sin^7(cos(4x)*cos(cos(4x))dcos(4x)/dx=8sin^7(cos(4

导热管也有液体导热的,导热管开焊导致温度高,两端温差大,就换,用手感觉出风口为热风属正常,如果CPU温度高还出凉风,换.还有CPU意外受热导致质量下降也能导致温度高,游戏太大使CPU使用率太大温度高.

运用公式sin2α=2sinαcosα8sin(π/32)cos(π/32)cos(π/16)cos(π/8)=4×2sin(π/32)cos(π/32)cos(π/16)cos(π/8)=4×sin

Cos[Pi/32]Cos[Pi/16]Cos[Pi/8]=1/(Sec[Pi/8]Sec[Pi/16]Sec[Pi/32])=-((-1)^(25/32)(1+(-1)^(1/16))(1+(-1)

只有类似例题、

cosπ/8=cos[(π/4)/2]=√[1+cos(π/4)]/2=√[1+(√2/2)]/2=(1/2)√(2+√2)cos(π/16)=cos[(π/6)/2]=√[1+cos(π/8)]/2

sin(sin(sinx))

直接反用2倍角公式就可以了：2sinαcosα=sin2αcos2α=cos^2(α/2)-sin^2(α/2)原式=2sinπ/4cosπ/4=sinπ/2=1

原式＝8cos[(α+β)+α]+5cos[(α+β)-α]=0把它折开,移项,合并就可得13cos(α+β)*cosα=3sin(α+β)*sinα可易得tan(α+β)×tanα=13/3

1-2cos²(π/8)=-[2cos²(π/8)-1]=-cos(π/4)=-(√2)/2这里是-2分之根号2这里注意用一个公式：cos2x=2cos²x-1

cos^4（π/8）+cos^4（3π/8）+cos^4（5π/8）+cos^4（7π/8）=2[cos(π/8)]^4+2[sin(π/8)]^4=2-[2sin(π/8)cos(π/8)]^2=2

(cosa)^2=(cos2a+1)/2(cosa)^2=(cos2a+1)^2/4cos(π/8))^4=(cosπ/4+1)^2/4=[3+2√2]/8cos(3π/8))^4=(cos3π/4+

是要化简吗?(cosπ/8+sinπ/8)(cos³3π/8-sin³3π/8)=(cosπ/8+sinπ/8)(cosπ/8-sinπ/8)(cos²3π/8+cos3

对θ求导是1/cos8θ*（-sin8θ）*8=-8tan8θ解毕~望采纳~一楼不对.楼主注意了

(cosπ/8+sinπ/8)(cos^3π/8+sin^3π/8)=[(cosπ/8+sinπ/8)^2](cos^2π/8-cosπ/8sinπ/8+sin^2π/8)=(1+2cosπ/8sin