(1)若点在抛物线上.
①求抛物线的表达式;
②当x为何值时y随x的增大而减小?
(2)若,当抛物线的最低点到x轴的距离恰好是1时,求a的值;
(3)已知、,连结,当抛物线与线段有交点时,该交点为P(点P不与A、B重合),将线段绕点P顺时针旋转得到线段,以、为邻边构造矩形,当抛物线在矩形内部(包含边界)图像所对应的函数的最大值与最小值的差为时,直接写出a的值.
同类型试题
y = sin x, x∈R, y∈[–1,1],周期为2π,函数图像以 x = (π/2) + kπ 为对称轴
y = arcsin x, x∈[–1,1], y∈[–π/2,π/2]
sin x = 0 ←→ arcsin x = 0
sin x = 1/2 ←→ arcsin x = π/6
sin x = √2/2 ←→ arcsin x = π/4
sin x = 1 ←→ arcsin x = π/2
y = sin x, x∈R, y∈[–1,1],周期为2π,函数图像以 x = (π/2) + kπ 为对称轴
y = arcsin x, x∈[–1,1], y∈[–π/2,π/2]
sin x = 0 ←→ arcsin x = 0
sin x = 1/2 ←→ arcsin x = π/6
sin x = √2/2 ←→ arcsin x = π/4
sin x = 1 ←→ arcsin x = π/2