1.当0≤x≤1时,不等式sin(πx/2)≥kx成立,则实数k的取值范围是_______.
2.在三角形ABC中,内角A、B、C的对边长分别为a、b、c,已知a^2-c^2=2b,且sinAcosC=3cosAsinC,求b
3.已知函数f(x)=sinX+tanX,项数为27的等差数列{An}满足An∈(-π/2,π/2),且公差d≠0,若f(A1)+f(A2)+f(A3)+....+f(A27)=0,则当k=_______时,f(Ak)=0.
4.已知函数f(x)=f′(π/4)cosx+sinx,则f(π/4)的值为________.
2.在三角形ABC中,内角A、B、C的对边长分别为a、b、c,已知a^2-c^2=2b,且sinAcosC=3cosAsinC,求b
3.已知函数f(x)=sinX+tanX,项数为27的等差数列{An}满足An∈(-π/2,π/2),且公差d≠0,若f(A1)+f(A2)+f(A3)+....+f(A27)=0,则当k=_______时,f(Ak)=0.
4.已知函数f(x)=f′(π/4)cosx+sinx,则f(π/4)的值为________.