import { useState } from 'react'; export default function ShowMe() { const [a, setA] = useState(1); const [b, setB] = useState(0); const [c, setC] = useState(0); const W = 320, H = 280, OX = 160, OY = 140, S = 20; const f = x => a*x*x + b*x + c; const vx = a !== 0 ? -b/(2*a) : 0; const vy = f(vx); const points = []; for (let px = 0; px <= W; px += 2) { const xv = (px - OX) / S; const yv = f(xv); const py = OY - yv * S; if (py > -50 && py < H + 50) points.push(`${px},${py}`); } return (

이차함수 포물선

y = {a}x² + {b}x + {c}

{[{label:'a', val:a, set:setA, min:-3, max:3, step:0.5, color:'#7c3aed'}, {label:'b', val:b, set:setB, min:-5, max:5, step:1, color:'#2563eb'}, {label:'c', val:c, set:setC, min:-5, max:5, step:1, color:'#059669'}].map(({label,val,set,min,max,step,color}) => (

{label} set(Number(e.target.value))} style={{ width:100 }} /> {val}

))}

{a > 0 ? '위로 볼록 (a>0)' : a < 0 ? '아래로 볼록 (a<0)' : '직선 (a=0)'} {a !== 0 && · 꼭짓점 ({vx.toFixed(2)}, {vy.toFixed(2)})}

); }