cos(4*pi() 180)
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∵sin(α+3π/4)=cos(α+π/4)=5/13cos(π/4-β)=sin(β+π/4)=3/5又-π/4
sinx=(√90)/10sin(π/4+2x)=sinπ/4cos2x+cosπ/4sin2x=√2/2(cos2x+sin2x)=√2/2(2cos²x-1+2sinxcosx)=√2/
解cos(a+π/4)=cos[(a+b)-(b-π/4)]=cos(a+b)cos(b-π/4)+sin(a+b)sin(b-π/4)由a,b∈(3pi/4,pi),sin(a+b)=-3/5,si
sin(a+b)=-3/5,a,b∈(3π/4,π),则cos(a+b)=4/5,sin(b-π/4)=12/13,b∈(3π/4,π),则cos(b-π/4)=-5/13.则cos(a+π/4)=c
y=(0.5+3*sin(x*pi/180)/(1+x.^2))*cos(x*pi/180)小数点不要乱加加小数点表示对矩阵中的每一个元素做运算,不加则表示对整个矩阵做运算此处x.^2是对x中每个元素
因为sin2π/7=2sinπ/7cosπ/7所以sinπ/7cosπ/7=(1/2)sin2π/7其实可以上下乘以22sinπ/7cosπ/7cos2π/7cos4π/7/(2sinπ/7)=sin
Console.WriteLine("cos(i*pi/180):", (Math.Cos(i*Math.PI/180)));Console.WriteLine(&quo
2sin(3x-3π/4)=2sin(3x-3π/4+3π/2-3π/2)=2sin(3x+3π/4-3π/2)=2sin(3x+3π/4+π/2-2π)=2sin(3x+3π/4+π/2)=-2co
试试这个吧:x=-pi:1/180*pi:pi;plot(sin(x),'r'); &nb
用二倍角公式.cos(x+π/3)=cos2(x/2+π/6)=1-2sin²(x/2+π/6)..
cos(-π/3)=cos(π/3)=1/2再问:cos(-a)=cosa对吗老暮,有没有哪个表说明这个啊?再答:对的,把a看成锐角,-a就是第四象限角,再由口决就可以得到了。
有点公式最基本的作用,可以将任意角的三角函数转化为锐角三角函数值cos(-19π/6) =cos(19π/6) =cos(2π+7π
f(x)=cos(2x-π/3)+2sin(x-π)sin(x+π/4)=cos(2x-π/3)-√2sinx(sinx+cosx)=[(cos2x)/2]+[√3(sin2x)/2]-[√2(1-c
[sin(α+pi)*cos(pi+α)*cos(α+2pi)]/[tan(pi+α)*cos^3(-α-pi)]=[(-sin(α))*(-cos(α))*cos(α)]/[tan(α)*(-cos
17pi/12
这里还有一个变量t没有定义范围假定t/T=[-11]r=-1:0.01:1;%t/Tq=cos(pi/8*(cos(pi*r)).^3-3*pi/8*cos(pi*r))+pi/4;plot(r,q)
分子=-sina*(-sina)*(-cosa)=-sina*sina*cosa分母=sina*(-cosa)所以结果是sina
asinπ/4cosx-acosπ/4sinx-bcosπ/4cosx-bsinπ/4sinx=asinπ/4cosx+acosπ/4sinx-bcosπ/4cosx+bsinπ/4sinxacosπ
/>因为:cos(a+b)=4/5,a+b∈[7pi/4,2pi].,所以:sin(a+b)=-3/5因为:cos(a-b)=-4/5,a-b∈[3pi/4,pi].,所以:sin(a-b)=3/5所