问题1:准线方程为x=2的抛物线的标准方程为( )
A: y²=-4x
B: y²=-8x
C: y²=4x
D: y²-6x=0
A: y²=-4x
B: y²=-8x
C: y²=4x
D: y²-6x=0
举一反三
- 【单选题】已知抛物线的准线方程是y=2则抛物线标准方程是 A. y²＝8x B. y²＝—8x C. X²＝8y D. X²＝-8y
- (4)()#include()extern()serial_initial()();()main()(){()int()a,b();()unsigned()int()x,y();()serial_initial()();()a=b=0xaa55();x=y=0xaa55;()printf("\n()a=%4x()b=%4x()x=%4x()y=%4x",a,b,x,y)();()a=a<<1();b=b>>1;()x=x<<1();y=y>>1;()printf("\n()a=%4x()b=%4x()x=%4x()y=%4x",a,b,x,y)();()printf("\n")();()printf("\n")();()printf("That()is()all.\n")();()while(1)();()}()______________________________________________________________________________________________________________________________
- 如下C程序的输出是什么？#include [stdio.h]void Func1 (int x, int y);void Func2 (int *x, int *y); int main() { int x = 3; int y = 4;Func1 (x, y); printf ("x = %d, y = %d\n", x, y);Func2(&x, &y); printf ("x = %d, y = %d\n", x, y);} void Func1 (int x, int y) { x = x + y; y = x - y; x = x - y; printf ("x = %d, y = %d\n", x, y);} void Func2 (int *x, int *y) { *x = *x + *y; *y = *x - *y; *x = *x - *y;;} A: x = 3, y = 4x = 3, y = 4x = 3, y = 4 B: x = 4, y = 3x = 4, y = 3x = 4, y = 3 C: x = 3, y = 4x = 3, y = 4x = 4, y = 3 D: x = 4, y = 3x = 3, y = 4x = 4, y = 3
- 问题6:已知抛物线的准线方程为x=3,则其标准方程为( ) A: y²=12x B: y²=-12x C: x²=12y D: x²=-12y
- 与圆x2+y2-4x=0外切，且与y轴相切的动圆圆心的轨迹方程为（）. A: y2=8x(x≥0) B: y=0(x＜0) C: y2=8x(x≥0)或y=0(x＜0) D: y2=4x(x≥0)