1-2sin²π/8=sinπ/4 - 知识问答

3个回答

f(x)=1-2sin^2(x+π/8)+2sin(x+π/8)*cos(x+π/8)=cos(2x+π/4)+sin(
fx=1-2sin^2(x+π/4)+2sin(x+π/8)cos(x+π/8)
2sin（πx/4-π/4）+6＜2sin（πx/4-3π/4）+8
计算,sin(π/12)-sin(5π/12)+2sin(π/8)sin(3π/8)
y=sin(π/4+x/2)sin(π/4-x/2) =sin(π/4+x/2)sin[π/2-(π/4+x/2)]
化简：[1+2sin(α+2π)*cos(α-2π)]/[sin(α+4π)+cos(α+8π)]
化简[sin(k-5π）cos(-2/π-k）cos(8π-k）]/[sin(k-3π/2）sin(-k-4π)]
y=4sin(πx/8+π/4-π)怎样变成y=-4sin(πx/8+π/4）过程~
为什么sin11π/3=sin（4π-π/3）=－sinπ/3=－根号3/2,sin（4π-π/3）=－sinπ/3我不
化简:sin(a+5π)cos(-π/2-a)·cos(8π-a)/sin(a-3π)·sin(-a-4π)