已知α为锐角,且sin2α+根号3倍cos2α=1,函数f(x)=2xcos(α-π/4)+sin(α+π/4) 1 求函数f(x)的表达式2 数列{an}的首项a1=1,a(n+1)=f(an),求数列的前n项和Sn
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![已知α为锐角,且sin2α+根号3倍cos2α=1,函数f(x)=2xcos(α-π/4)+sin(α+π/4) 1 求函数f(x)的表达式2 数列{an}的首项a1=1,a(n+1)=f(an),求数列的前n项和Sn](/uploads/image/z/2523394-10-4.jpg?t=%E5%B7%B2%E7%9F%A5%CE%B1%E4%B8%BA%E9%94%90%E8%A7%92%2C%E4%B8%94sin2%CE%B1%2B%E6%A0%B9%E5%8F%B73%E5%80%8Dcos2%CE%B1%3D1%2C%E5%87%BD%E6%95%B0f%28x%29%3D2xcos%28%CE%B1-%CF%80%2F4%29%2Bsin%28%CE%B1%2B%CF%80%2F4%29+1+%E6%B1%82%E5%87%BD%E6%95%B0f%EF%BC%88x%EF%BC%89%E7%9A%84%E8%A1%A8%E8%BE%BE%E5%BC%8F2+%E6%95%B0%E5%88%97%7Ban%7D%E7%9A%84%E9%A6%96%E9%A1%B9a1%3D1%2Ca%EF%BC%88n%2B1%EF%BC%89%3Df%EF%BC%88an%EF%BC%89%2C%E6%B1%82%E6%95%B0%E5%88%97%E7%9A%84%E5%89%8Dn%E9%A1%B9%E5%92%8CSn)
已知α为锐角,且sin2α+根号3倍cos2α=1,函数f(x)=2xcos(α-π/4)+sin(α+π/4) 1 求函数f(x)的表达式2 数列{an}的首项a1=1,a(n+1)=f(an),求数列的前n项和Sn
已知α为锐角,且sin2α+根号3倍cos2α=1,函数f(x)=2xcos(α-π/4)+sin(α+π/4) 1 求函数f(x)的表达式
2 数列{an}的首项a1=1,a(n+1)=f(an),求数列的前n项和Sn
已知α为锐角,且sin2α+根号3倍cos2α=1,函数f(x)=2xcos(α-π/4)+sin(α+π/4) 1 求函数f(x)的表达式2 数列{an}的首项a1=1,a(n+1)=f(an),求数列的前n项和Sn
sin2α+根号3倍cos2α= 2sin(2α+π/3) = 1
sin(2α+π/3) = 1/2
2α+π/3 = 5π/6
α = π/4
f(x)=2xcos(α-π/4)+sin(α+π/4) = 2x + 1
a1 = 1
a2 = 2+1
a3 = 7
an = 2^n - 1
Sn = sum(2^n - 1)
(1)2(cos2acos30度+sin2asin30度)=1,则cos(2a-30度)=1/2,所以2a-30度=60度,a=45度,所以f(x)=2x,第二题我就不懂了,请谅解
已知函数f(x)=cos3/2xcosx/2-sin3/2xsinx/2+2根号3sinxcosx
=cos(3/2x+x/2)+根号3sin2x
=cos2x+ 根号3sin2x
=2sin(2x+π/6)
(1) f(π/12)=2sin(π/6+π/6)=2sin(π/3)=√3
(2)若x属于(-5/24π,π/4)
2x+π/6属于(-π/4,2π/3)
当2x+π/6=π/2,即 x=π/6 时 f(x)的最大值=2