拋物線的頂點(diǎn)在原點(diǎn),對(duì)稱軸為坐標(biāo)軸, 且經(jīng)過點(diǎn)(-2,3), 只有兩種可能:
1. 開口向上: y = a(x - 0)² + 0 = ax²; 代入(-2, 3): 3 = a(-2)², a = 3/4, y = 3x²/4
2. 開口向左: y² = -bx = -bx; 代入(-2, 3): 9 = -b(-2), b =9/2;y²= -9x/2
拋物線的頂點(diǎn)在原點(diǎn),對(duì)稱軸為坐標(biāo)軸, 且經(jīng)過點(diǎn)(-2,3), 只有兩種可能:
1. 開口向上: y = a(x - 0)² + 0 = ax²; 代入(-2, 3): 3 = a(-2)², a = 3/4, y = 3x²/4
2. 開口向左: y² = -bx = -bx; 代入(-2, 3): 9 = -b(-2), b =9/2;y²= -9x/2