sin2x与cos2x之间的转化

禄冰航2831y=sinx与y=cosx可以怎样转换y=sin2x与y=cos2x呢? -
班邢耐18540048875 ______[答案] sin^x+cos^x=1 sinx=cos(π/2-x) sin2x=2sinxcosx cos2x=cos^x-sin^x=1-2sin^x=2cos^x-1 没见过两者直接转换的 496015736童鞋回答很强悍,滴汗啊

禄冰航2831化简y=sin2x+cos2x -
班邢耐18540048875 ______[答案] y=sin2x+cos2x =√2sin(2x+π/4).

禄冰航2831sin2x - cos2x最值 -
班邢耐18540048875 ______[答案] y=sin2x-cos2x =√2(√2/2sin2x-√2/2cos2x) =√2(cosπ/4sin2x-sinπ/4cos2x) =√2sin(2x-π/4) 因此-√2

禄冰航2831sin2x+cos2x=根号2倍(2x+四分之派),为什么?sin2x+cos2x=根号2倍sin(2x+四分之派),为什么?那为什么第一步要先提出一个根号2呢? -
班邢耐18540048875 ______[答案] 由sinπ/4=cosπ/4=根号2/2sin2x+cos2x=根号2(sin2x*根号2/2+cos2x*根号2/2)=根号2*(sin2x*cosπ/4+cos2x*sinπ/4)再由sin(a+b)=sina*cosb+sinb*cosa所以,原式=根号2*(sin(2x+π/4))你的式子好像少了个sin....

禄冰航2831函数Y=SIN2X+COS2X的值域为多少? -
班邢耐18540048875 ______[答案] sin2x+cos2x=√2(√2/2sin2x+√2/2*cos2x)=√2(cospai/4sin2x+sinpai/4cos2x)=√2sin(2x+pai/4)所以...公式:cosasinb+sinacosb=sin(a+b) y=sin2x+cos2x =√2(sin45sin2x+cos45cos2x) =√2cos(45-2x)∈[-√2,√2]...

禄冰航2831sin2x +cos2x -
班邢耐18540048875 ______ 此处采用弧度制 asinA+bcosA=√(a^2+b^2)sin(A+M) ,(tanM=b/a) 所以sin2x +cos2x=√(1²+1²)sin(2x+M), tanM=1/1=1, 所以M=π/4, 所以sin2x +cos2x=√(1²+1²)sin(2x+M) =√2sin(2x+π/4)

禄冰航2831 - 2sin2x+cos2x的化简结果是什么? -
班邢耐18540048875 ______[答案] -2sin2x+cos2x=cos2x-2sin2x =√5[1/√5cos2x-2/√5sin2x] =√5cos(2x+α) 其中cosα=1/√5 不过这一般不用化解!

禄冰航2831sin2x cos2x怎么化简 -
班邢耐18540048875 ______ sin2x cos2x=(1/2)sin4x

禄冰航2831sin2x+cos2x怎么化简 -
班邢耐18540048875 ______ sin2x+cos2x = 根2·【cos45·sin2x + sin45·cos2x】 = 根2·sin[2x + 45]

禄冰航2831sinxsinx转化为sin2x与cos2x -
班邢耐18540048875 ______[答案] 由cos2x=(cosx)^2-(sinx)^2 得(sinx)^2=(1-cos2x)/2 由sin2x=2sinxcosx 得(sinx)^2={1-√[1-(sin2x)^2]}/2