cos+π+α+等于多少为什么

郁秀娇1408cos(π+α)= - 1/3,sin(3π/2 - α)= -
万命仪17838256148 ______ cos(π+α)=-1/3,sin(3π/2-α)=-1/3 sin(π/3+α)=1/3,cos(5π/6+α)=-1/3 sin(α-π/4)=1/3,cos(π/4+α)=-1/3

郁秀娇1408cos(x+π)等于多少 -
万命仪17838256148 ______ cos(x-π/2)等于sinx. 解答过程如下: cos(x-π/2) =cos(-(π/2-x))(这里是把x-π/2化成-(π/2-x)) =cos(π/2-x)(这里是因为cos-x=cosx,cosx是一个偶函数) =sinx 扩展资料: 设α为任意角,弧度制下的角的表示: (1)sin(π+α)=-sinα. (2)cos(π+α...

郁秀娇1408cos(2π+α)=? -
万命仪17838256148 ______ coa(2π+α)=coaα 以为一个角加上2π相当于还是原来那个角 如果还有什么不明白的地方欢迎再问哦亲~

郁秀娇1408cos( - 派 - a)是多少 -
万命仪17838256148 ______[答案] cos(-π-a)=cos(π+a)=-cosa 哪里不懂请追问哦

郁秀娇14086.cos330°等于多少?7.cos(π+α)= - 1/2,3π/2 -
万命仪17838256148 ______[答案] 6.cos330°=cos(360º-30º)=cos30º=√3/2 7.cos(π+α)=-1/2 ==>cosα=1/2 ∵3π/23x0²+1=4 ==>x0=±1 x0=1 ,f1)=0,P0(1,0) x0=-1,f(-1)=-4 ,P0(1,-4) P0(1,0),P0(1,-4)均符合题意 答案:D.(1,0)或(-1,-4) 9.函数f(x)=(x-3)e^X的单调递增区间是多少? f'(x)=e^...

郁秀娇1408已知cos(π+α)= - 1/2,且α是第四象限角,计算{sin[α+(2n+1)π]+sin[α - (2n+1)π]}计算{sin[α+(2n+1)π]+sin[α - (2n+1)π]}÷[sin(α+2nπ)*cos(α - 2nπ)] (n∈Z) -
万命仪17838256148 ______[答案] cosα=-cos(π+α)=1/2 原式=[sin(α+π)+sin(α-π)]/(sinαcosα) =-2sinα/(sinαcosα) =-2/cosα =-4

郁秀娇1408cos(kπ - a)=cos(kπ+a),就是cos( - π - a)等于多少 -
万命仪17838256148 ______[答案] cos(kπ-a)=cos(kπ+a),是对的 cos(-π-a)=cos(π+a)=-cosa

郁秀娇1408cos(π/6 - α)=m,m绝对值小于等于1,求cos(5π/6+α)+sin(2π/3-α) -
万命仪17838256148 ______[答案] cos(5π/6+α)=cos[π-(π/6-α)]=-cos(π/6-α)=-m sin(2π/3-α)=cos[π/2-(2π/3-α)]=cos(-π/6+α)=cos(π/6-α)=m 所以原式=0

郁秀娇1408cos(π+α)= - 1/2,3π/2<α<2π,则sin(α+3π)等于多少? -
万命仪17838256148 ______[答案] 3π/2<α<2π 5π/2<α+π<3π 周期为2π π/2<α+π<π,α+π在第二象限,cos为负,sin为正 cos(π+α)=-1/2 sin(α+3π)=sin(α+3π-2π)=sin(α+π)=√3/2

郁秀娇1408已知cosα= - 4/5,α∈(π/2,π),则cos(4/π - α)等于多少? -
万命仪17838256148 ______[答案] cosα=-4/5,α∈(π/2,π), sina=3/5 cos(π/4-a) =cosπ/4cosa+sinπ/4sina =√2/2*(-4/5)+√2/2*3/5 =-√2/10