已知cos(75度 x)

f(cosx)=cos3x=cos(2x+x)=cos2xcosx-sin2xsinx=(2cos²x-1)cosx-(2sinxcosx)sinx=2cos³x-cosx-2si

f(x)=cos(2x-π/6)-cos(2x+π/6)+2cos²x=cos2xcos(π/6)+sin2xsin(π/6)-[cos2xcos(π/6)-sin2xsin(π/6)]+2

sin(90度+x)-cos(270度-x）=cosx+cos(90-x)=cosx+sinx=0.2所以（cosx+sinx）^2=(cosx)^2+2*sinx*cosx+(cosx)^2=1+2

sin(180度+x)=-0.5=-sinxsinx=0.5cosx=+-根号3/2=cos(360度+x)

1a+b=(cos(3x/2)-sin(x/2),sin(3x/2)-cos(x/2))所以：|a+b|^2=(cos(3x/2)-sin(x/2))^2+(sin(3x/2)-cos(x/2))^2

题目是否为cos(-255度-x)+sin(435+x)cos(-255度-x)+sin(435+x)=cos(255度+x)+sin(75度+x)=-cos(75度+x)+sin(75度+x)又co

整理方程,得y=1+2sinxcosx+2(cosx)^2利用降幂公式和二倍角公式,得y=sin2x+cos2x+2再利用辅助角公式,得y=根号2*sin(2x+π/4)+2所以当2x+π/4属于[2

∵-π

cos(x+75)=1/3sin(x-105)=sin(x-15-90)=-sin[90-(x-15)]=-cos(x-15)x在第三象限cos(x+75)>0,所以x+75在第四象限所以sin(x+

f'(x)=-1/2*sin(x/2)*[sin(x/2)-cos(x/2)]+cos(x/2)[1/2cos(x/2)+1/2sin(x/2)]=-1/2*sin²(x/2)+1/2sin

f(x)=cos(2x-π/3)-(cos^2x-sin^2x)=cos(2x-π/3)-cos2x=2sin(2x-π/6)sinπ/6=sin(2x-π/6)因为y=sinx的单减区间为[π/2+

f(x)=cos(2x-π\3)+sin²x-cos²x=1/2cos2x+√3/2sin2x-cos2x=√3/2sin2x-1/2cos2x=-cos(2x+π\3)-1

这个好像是数学里面的吧,没编程什么事吧!cos(15度-x)=cos(90度-(75度+x))=sin(75度+x)因为-180度

cos(105度-x)=-cos(180-105+x)=-cos(75+x)=-1/31/3=cos（75+x)=sin(90-75-x)=sin(15-x)=-sin(x-15)所以sin(x-15

cos2x=3/5,sin2x=±4/5sin^4x+cos^4x=（-sinx^2+cosx^2)^2+2sinx^2cosx^2=cos2x^2+1/2sin2x=9/25±2/5=19/25,或

你确定第一个符号是加号不是乘号?

已知f(cosx)=cos3x,则f(sinx)=要有过程sinx=cos(π/2-x)f(sinx)=f(cos(π/2-x))=cos3(π/2-x)=sin3x

sinx=2cosx,sin^2x=4cos^2xsin^2x=4-4sin^2x,sin^2x=4/5(cosx+sinx)/(cosx-sinx)+sin^2x=(1+tanx)/(1-tanx)

f(x)=2cosx*sinx-2cosx^2+1f(x)=sin2x-cos2xf(x)=根号2*sin(2x-45)周期T=π

原式平方可求出2SIN@COS@等于8,(SIN@-COS@）的平方等于1-2SIN@COS@=-7无解,是不是算错了,算出SIN@COS@后再除以（SIN@的平方+COS@得平方）,齐次式,分子分母