f(x)=4sin(2x+60度)
设不相等的实数x1 x2属于(0,180)
且f(x1)=f(x2)=-2,求x1+x2的值
f(x)=4sin(2x+60度)
设不相等的实数x1 x2属于(0,180)
且f(x1)=f(x2)=-2,求x1+x2的值
令f(x)=4sin(2x+π/3)=-2,则sin(2x+π/3)=-1/2
x∈(0,π),∴2x+π/3∈(π/3,7π/3)
∴2x+π/3=7π/6或11π/6
∴2x1+π/3+2x1+π/3=7π/6+11π/6=3π
即2(x1+x2)+2π/3=3π
∴x1+x2=(3π-2π/3)/2=7π/6