sin(x-1/4π)等于
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(1+cotx)sin^2x=sin^2x+sinxcosx2sin(x+π/4)sin(x-π/4)=根号2(sinx+cosx)*根号2/2(sinx-cosx)=sin^2x-cos^2xf(x
sinx+cosx=m平方sin²x+cos²x+2sinxcosx=m²1+2sinxcosx=m²sinxcosx=(m²-1)/2所以sin&s
sin(2x+π)等于-sin(2x)
sin(PI/6+2x)=cos(PI/2-PI/6-2x)=cos(PI/3-2x)=cos(2*(PI/6-x))=1-2*sin(PI/6-x)^2=1-2*(1/4)^2=7/8tan70*c
根据sinπx=1/(1-x)其绝对值小于等于1,因此x大于2或者x小于0,区间【2,4】内,即【-2,0】和【2,4】,画y=sinπx和y=1/(1-x)的图形,根据对称性和周期性可看出在两区间内
2sin^2[(π/4)+x]+根号3(sin^x-cos^x)-1=-(1-2sin^2[(π/4)+x)-√3cos2x=-cos(π/2+2x)-√3cos2x=sin2x-√3cos2x=2[
sin(x-3π/4)=sin[π-(π/4-x)]=sin(π/4-x)=-sin(x-π/4)sin(x-3π/4)cos(x-π/4)=-sin(x-π/4)cos(x-π/4)=-sin(2x
sin(π/4-x)=sin(π/4)cosx-cos(π/4)sinx=(√2/2)cosx-(√2/2)sinx;cos(x+π/4)=cosxcos(π/4)-sinxsin(π/4)=(√2/
因为sin²a+cos²a=1所以cos²a=1-sin²a所以左边=(sin²a+cos²a)(sin²a-cos²a
因为|sinx|>=0,|cosx|>=0,所以|sinx|+|cosx|>=0所以平方(|sinx|+|cosx|)^2=(SINX)^2+(COSX)^2+2|SINX|*|COSX|=1+2|S
积化和差,sin(a+b)=sinacosb+cosasinb,1sin(a-b)=sinacosb-cosasinb,21-2,sin(a+b)-sin(a-b)=2sinacosb;令a=mx,b
sin(x-4分之π)=-sin(π/4-x)=-sin[π/2-(π/4+x)]=-cos[(π/4)+x]=1/3所以:cos[(π/4)+x]=-1/3
f(5π/4)=2sin(5π/12-π/6)=2sin(3π/12)=2sin(π/4)=√2
新人教版高中数学必修四第三章三角恒等变换·1、两角和与差的正弦、余弦和正切.北师大版高中数学必修四第三章三角恒等变形·1、两角和与差的三角函数.cos(x+π/4)=cosxcos(π/4)-sinx
f(x)=(1+1/tanx)*(sinx)^2-2sin(x+π/2)sin(x-π/4)=(1+cosx/sinx)*(sinx)^2+2sin(x+π/4)cos[(x-π/4)+π/2]=(s
【参考答案】D[sin(π/2-x)+sin(π-x)]/[cos(-x)+sin(2π-x)]=2009根据诱导公式,化简(cosx+sinx)/(cosx-sinx)=2009左边分子分母同时除以
再问:是y=1/x-1啊,再答:这个很类似,现在没有时间回答你的问题了,抱歉!
sin^4x-sin^2xcos^2x+cos^4x=sin^4x+2sin^2xcos^2x+cos^4x-3sin^2xcos^2x=(sin^2x+cos^2x)^2-3sin^2xcos^2x
仅考虑实数,有x=pi/2