已知抛物线Y=4X^2与直线y=kx-1有唯一交点,求k的值.

问题描述:

已知抛物线Y=4X^2与直线y=kx-1有唯一交点,求k的值.

k=4
将Y=4X^2与y=kx-1联立方程得:
Y=4X^2(1)
y=kx-1(2)
将(2)代入(1)
4X^2-kx+1=0
又抛物线Y=4X^2与直线y=kx-1有唯一交点,即方程有唯一解
则,配方得k=4