sin2a+cos2a等于多少
@侯群1256:正弦和余弦sin2a+cos2a=
郁瑗15368166733…… sin2a+cos2a =√2(sin2a·√2/2+√2/2·cos2a) =√2(sin2a·cosπ/4+sinπ/4·cos2a) ==√2sin(2a+π/4).
@侯群1256:sina+2cosa=0,则sin2a+cos2a= -
郁瑗15368166733…… sina+2cosa=0 sin^2a+cos^2a=1 →cos^2a=1/5,sin^2a=4/5,sinacosa=-2/5 Sin2a= 2sinacosa=-4/5 又cos2a=2cos^2a-1=→cos2a=-23/25 sin2a+cos2a=-4/5+-23/25=-43/25
@侯群1256:sin2a+cos2a =??
郁瑗15368166733…… =根号2·sin(2a+四分之派)
@侯群1256:cos2a+sin2a等于什么😊 -
郁瑗15368166733…… sin2a=sin(a+a)=sinacosa+cosasina=2sinacosa cos2a=cos(a+a)=cosacosa-sinasina=cosa^2-sina^2=1-sina^2-sina^2=1-2sina^2=cosa^2-(1-cos^2)=2cosa^2-1
@侯群1256:以知A是一个锐角,则Sin2A+Cos2A=?...麻烦大家帮我解下好吗? 注意写过程哦.谢谢了
郁瑗15368166733…… 解;sin2A+cos2A=√2(sin2A*√2/2+cos2A*√2/2) =√2sin(2A+π/4)
@侯群1256:sin2A + cos2A = 1什么意思、 - 作业帮
郁瑗15368166733…… [答案] 平方下,(sin2a+cos2a)^2=1^2 化简得sin(2a)^2+cos(2a)^2+2sin(2a)cos(2a)=1 又sin(2a)^2+cos(2a)^2=1 2sin(2a)cos(2a)=0 有两个根 sin2a=0 或者cos2a=0 a=0 或者a=45
@侯群1256:sin2A+cos2A(0°<A<90°)等于 -
郁瑗15368166733…… sin2A+cos2A=2sinA*cosA+cosA^2--sinA^2
@侯群1256:sin2a和cos2a 分别等于什么 - 作业帮
郁瑗15368166733…… [答案] sin2a=sin(a+a)=sinacosa+cosasina=2sinacosa cos2a=cos(a+a)=cosacosa-sinasina=cosa^2-sina^2=1-sina^2-sina^2= 1-2sina^2=cosa^2-(1-cos^2)=2cosa^2-1
@侯群1256:已知∠A为锐角,则sin2A+cos2A= - ----- -
郁瑗15368166733…… sin2A+cos2A=1. 故答案是:1.
@侯群1256:三角函数cosa=3sina,sin2a+cos2a=?这题怎么
郁瑗15368166733…… sin2a+cos2a=2sinacosa+1-2sin^2a=2sina(3sina)+sin^2a+cos^2a-2sin^2a=6sin^2a+sin^2a+9sin^2a-2sin^2a=14sin^2a
郁瑗15368166733…… sin2a+cos2a =√2(sin2a·√2/2+√2/2·cos2a) =√2(sin2a·cosπ/4+sinπ/4·cos2a) ==√2sin(2a+π/4).
@侯群1256:sina+2cosa=0,则sin2a+cos2a= -
郁瑗15368166733…… sina+2cosa=0 sin^2a+cos^2a=1 →cos^2a=1/5,sin^2a=4/5,sinacosa=-2/5 Sin2a= 2sinacosa=-4/5 又cos2a=2cos^2a-1=→cos2a=-23/25 sin2a+cos2a=-4/5+-23/25=-43/25
@侯群1256:sin2a+cos2a =??
郁瑗15368166733…… =根号2·sin(2a+四分之派)
@侯群1256:cos2a+sin2a等于什么😊 -
郁瑗15368166733…… sin2a=sin(a+a)=sinacosa+cosasina=2sinacosa cos2a=cos(a+a)=cosacosa-sinasina=cosa^2-sina^2=1-sina^2-sina^2=1-2sina^2=cosa^2-(1-cos^2)=2cosa^2-1
@侯群1256:以知A是一个锐角,则Sin2A+Cos2A=?...麻烦大家帮我解下好吗? 注意写过程哦.谢谢了
郁瑗15368166733…… 解;sin2A+cos2A=√2(sin2A*√2/2+cos2A*√2/2) =√2sin(2A+π/4)
@侯群1256:sin2A + cos2A = 1什么意思、 - 作业帮
郁瑗15368166733…… [答案] 平方下,(sin2a+cos2a)^2=1^2 化简得sin(2a)^2+cos(2a)^2+2sin(2a)cos(2a)=1 又sin(2a)^2+cos(2a)^2=1 2sin(2a)cos(2a)=0 有两个根 sin2a=0 或者cos2a=0 a=0 或者a=45
@侯群1256:sin2A+cos2A(0°<A<90°)等于 -
郁瑗15368166733…… sin2A+cos2A=2sinA*cosA+cosA^2--sinA^2
@侯群1256:sin2a和cos2a 分别等于什么 - 作业帮
郁瑗15368166733…… [答案] sin2a=sin(a+a)=sinacosa+cosasina=2sinacosa cos2a=cos(a+a)=cosacosa-sinasina=cosa^2-sina^2=1-sina^2-sina^2= 1-2sina^2=cosa^2-(1-cos^2)=2cosa^2-1
@侯群1256:已知∠A为锐角,则sin2A+cos2A= - ----- -
郁瑗15368166733…… sin2A+cos2A=1. 故答案是:1.
@侯群1256:三角函数cosa=3sina,sin2a+cos2a=?这题怎么
郁瑗15368166733…… sin2a+cos2a=2sinacosa+1-2sin^2a=2sina(3sina)+sin^2a+cos^2a-2sin^2a=6sin^2a+sin^2a+9sin^2a-2sin^2a=14sin^2a