2cos2x等于sin2x

申艺昌3820y=sin2x - cos2x+1为什么等于√2sin(2x - π/4)+1 -
胥祥汤18097401053 ______ 解;y=sin2x-cos2x+1=√2(√2/2sin2x-√2/2cos2x)+1=√2sin(2x-π/4)+1 asin α+bcosα=√a²+b² sin(α+β) tanβ=b/a 比如上面那题 tanπ/4=1/1=1

申艺昌3820f(x)=2cos2x+sin^2x,化简.详细! -
胥祥汤18097401053 ______ 辅助角公式啊 a>0时 asinx bcosx=sqr(a^2 b^2)sin(x arctan b/a) 所以f(x)=sqr(5)sim(2x arctan2)

申艺昌38202sin^2xcos^2x=(sin2x)^2吗?不是的话等于什么 -
胥祥汤18097401053 ______[答案] 等于的 把sin^2x(和cos^2x)看成一个整体 而此时的sinx就是sin^2x了

申艺昌3820f(x)=2cos2x+sin^2x,化简.详细步骤! -
胥祥汤18097401053 ______[答案] cos2x=cos^2 x-sin^2 x 2cos2x=2cos^2 x-2sin^2 x f(x)=2cos^2 x-sin^2x =cos2x+1-sin^2x =cos2x+1+(1-cos2x)/2 =cos2x /2 +3/2

申艺昌3820求证:sinx(1+cos2x)=sin2xcosx
胥祥汤18097401053 ______ sinx(1+cos2x)=sinx(1+(cosx)^2-(sinx)^2)=2sinx(cosx)^2=sin2xcosx复制搜索复制搜索

申艺昌3820为什么sin2x+cos2x=2sin(2x+π/4) -
胥祥汤18097401053 ______[答案] sin2x+cos2x=(根号下2)sin(2x+π/4) sin2x+cos2x=(根号下2)[根号下2/2sian2x+根号下2/2cos2x] =(根号下2)[cosπ/4sin2x+sinπ/4cos2x] =(根号下2)sin(2x+π/4)

申艺昌3820为什么2sin^2x=1 - cos2x -
胥祥汤18097401053 ______[答案] cos2x=cos(x+x) =cosxcosx-sinxsinx =cos²x-sin²x =1-sin²x-sin²x cos2x=1-2sin²x 所以 2sin²x=1-cos2x

申艺昌3820『急求』1/2sin2x+1/2cos2x怎么等于√2/2sin(2x+π/4) -
胥祥汤18097401053 ______ =√2/2(√2/2cos2x+√2/2sin2x) =√2/2(sinπ/4cosπ/4+sinπ/4cosπ/4)=√2/2sin(2x+π/4)

申艺昌3820y=sin{2(x+4/π)}+1怎么化简成y=2cos2x -
胥祥汤18097401053 ______[答案] y=sin{2(x+4/π)}+1中4/π应是π/4吧?那y=sin{2(x+π/4)}+1=sin(2x+π/2)+1=cos2x+1,因为cos2x=(cosx)的二次方-(sinx)的二次方所以cos2x+1=cos2x=(cosx)的二次方-(sinx)的二次方+1因为(cosx)的...

申艺昌3820求解2sin2x - 2cos2x是怎么得到2倍根号2sin(2x - π/4), -
胥祥汤18097401053 ______[答案] 提2倍根号2出来,2倍根号2(根号2/2 sin2x-根号2/2 cos2x)=2倍根号2(sin2x cosπ/4-cos2x sinπ/4)=2倍根号2sin(2x-π/4)