将x=c代入x²/a²-y²/b²=1--->|y|=b²/a ∠PF1F2=30°--->b²/a=(2c)tan30°--->√3b²=2ac --->3(b²)²=4a²(a²+b²) --->3(b²/a²)²-4(b²/a²)-4=0 --->(b²/a²-2)(3b²/a²+2)=0 --->b²/a²=2 --->b/a=√2 --->双曲线的渐近线方程为：y=±√2x
