求椭圆焦点问题!急救!x^2/(m-2)+y^2/(m+5)=1的焦点坐标A(+ -7,0) B(0,+ -7) C(+ -根号7,0) D(0,+ -根号7)
来源:学生作业帮助网 编辑:作业帮 时间:2024/07/07 11:05:15
![求椭圆焦点问题!急救!x^2/(m-2)+y^2/(m+5)=1的焦点坐标A(+ -7,0) B(0,+ -7) C(+ -根号7,0) D(0,+ -根号7)](/uploads/image/z/14754409-25-9.jpg?t=%E6%B1%82%E6%A4%AD%E5%9C%86%E7%84%A6%E7%82%B9%E9%97%AE%E9%A2%98%21%E6%80%A5%E6%95%91%21x%5E2%2F%28m-2%29%2By%5E2%2F%28m%2B5%29%3D1%E7%9A%84%E7%84%A6%E7%82%B9%E5%9D%90%E6%A0%87A%28%2B+-7%2C0%29+B%280%2C%2B+-7%29+C%28%2B+-%E6%A0%B9%E5%8F%B77%2C0%29+D%280%2C%2B+-%E6%A0%B9%E5%8F%B77%29)
x){ْO=oYi^.a鳩+5ru4+,mSM[Z jΝlA{``TD&H`Xmˠ9,F;l2|YKؕgty/5>]ɮ8#g
Ov/}ڿN}:gE䋽[҃V4N$k$&ATem͑mCC(ЁXF 1 ,ZK
求椭圆焦点问题!急救!x^2/(m-2)+y^2/(m+5)=1的焦点坐标A(+ -7,0) B(0,+ -7) C(+ -根号7,0) D(0,+ -根号7)
求椭圆焦点问题!急救!
x^2/(m-2)+y^2/(m+5)=1
的焦点坐标
A(+ -7,0) B(0,+ -7) C(+ -根号7,0) D(0,+ -根号7)
求椭圆焦点问题!急救!x^2/(m-2)+y^2/(m+5)=1的焦点坐标A(+ -7,0) B(0,+ -7) C(+ -根号7,0) D(0,+ -根号7)
根据题意,因为a^2始终要大于b^2,所以可知椭圆焦点在Y轴上.
所以a^2=m+5,b^2=m-2
所以c^2=a^2-b^2=m+5-m-2=7
所以c=根号7
所以焦点坐标为(0,+ -根号7)
选D