已知函数f(x)=2sin(1/3x-30°),x属于R,(1)求f(5π/4)的值(2)设α,β∈[0,π/2],f(3α+π/2)=10/13,f(3β+2π)=6/5,求tanα·tanβ的值

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已知函数f(x)=2sin(1/3x-30°),x属于R,(1)求f(5π/4)的值(2)设α,β∈[0,π/2],f(3α+π/2)=10/13,f(3β+2π)=6/5,求tanα·tanβ的值

已知函数f(x)=2sin(1/3x-30°),x属于R,(1)求f(5π/4)的值(2)设α,β∈[0,π/2],f(3α+π/2)=10/13,f(3β+2π)=6/5,求tanα·tanβ的值
已知函数f(x)=2sin(1/3x-30°),x属于R,(1)求f(5π/4)的值(2)设α,β∈[0,π/2],f(3α+π/2)=10/13,f(3β+2π)=6/5,求tanα·tanβ的值

已知函数f(x)=2sin(1/3x-30°),x属于R,(1)求f(5π/4)的值(2)设α,β∈[0,π/2],f(3α+π/2)=10/13,f(3β+2π)=6/5,求tanα·tanβ的值
f(x)=2sin(x/3-30°)=2sin(x/3-π/6)
(1)f(5π/4)=2sin(5π/12-π/6)=2sinπ/4=√2.
(2)f(3α+π/2)=2sin(α+π/6-π/6)=2sinα=10/13、sinα=5/13、cosα=12/13、tanα=5/12.
f(3β+π/2)=2sin(β+π/6-π/6)=2sinβ=6/5、sinβ=3/5、cosβ=4/5、tanβ=3/4.
tanα·tanβ=(5/12)*(3/4)=5/9.