Tolong ya

<p>Jawaban yang tepat adalah <strong>bola tidak akan masuk ke keranjang</strong></p><p>&nbsp;</p><p>Pembahasan :</p><p>Misalkan fungsi kuadrat<br>y = ax2 + bx + c<br>Tinggi orang = 170 cm = 1,7 m.&nbsp;</p><p>Koordinat bola awal adalah (0, 1,7)<br>Dengan demikian posisi dari keranjang adalah (4, 3).&nbsp;</p><p>Koordinat dari titik optimum adalah (4½, 2½)<br>Maka didapat persamaan :<br>x_p = -b/2a</p><p>4½ = -b/2a</p><p>9/2 = -b/2a</p><p>18a/2 = -b</p><p>9a = -b</p><p>b = -9a &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; (1)</p><p>&nbsp;</p><p>y_p = (b² - 4ac)/-4a</p><p>2½ = (b² - 4ac)/-4a</p><p>5/2 = (b² - 4ac)/-4a</p><p>-20a/2 = b² - 4ac</p><p>-10a = b² - 4ac</p><p>b² - 4ac = -10a &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;(2)</p><p>&nbsp;</p><p>c = 1,7 &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;(3)</p><p>&nbsp;</p><p>Substitusikan (1) dan (3) ke persamaan (2)</p><p>b² - 4ac = -10a</p><p>(-9a)² - 4a(1,7) = -10a</p><p>81a² - 6,8a = -10a</p><p>81a² - 6,8a + 10a = 0</p><p>81a² + 3,2a = 0 &nbsp; &nbsp; &nbsp;(dikalikan 10 untuk menghilangkan desimal)</p><p>810a² + 32a = 0&nbsp;</p><p>a(810a + 32) = 0</p><p>a = 0 atau a = -32/810</p><p>&nbsp;</p><p>Karena bentuknya parabola maka a ≠ 0 sehingga</p><p>a = -32/810 dan b = -9(-32/810)</p><p>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;b = 32/90</p><p>dengan demikian fungsinya menjadi</p><p>y (x) = -32/810 x² + 32/90 x + 1,7</p><p>Posisi keranjang (4,3)</p><p>x = 4</p><p>y = -32/810 (4)² + 32/90(4) + 1,7</p><p>&nbsp; &nbsp; = -32/810 (16) + 32/90(4) + 1,7</p><p>&nbsp; &nbsp; = -0,63 + 1,42 + 1,7</p><p>&nbsp; &nbsp; = 2,49</p><p>&nbsp;</p><p>y ≠ 3 maka lemparan tidak akan masuk keranjang</p><p>&nbsp;</p>