等轴双曲线C的中心在原点,焦点在x轴上,C与抛物线y2=16x的准线交于A,B两点,AB=43;则C的实轴长为( )
如图所示,一束光线与水平面成45°角,从空气斜射入水中,由此可以断定,该光线所对应的反射光线与折射光线之间的夹角( )
70+80____70+60 5800–800____6000–3000 130+70____200+20
700–90____700–80 1200–200____1000+200 500–50____400+50
100+50____200–60 100–60____100-70