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受欢迎的代数 >

-13=8t+(0.5)(-9.8)t^2

解答

- 13 = 8 t + (0.5) (- 9.8) t^{2}

解答

t = - \frac{- 8 + 318.8}{9.8}, t = \frac{8 + 318.8}{9.8}

+1

十进制

t = - 1.00560 \dots, t = 2.63826 \dots

求解步骤

- 13 = 8 t + (0.5) (- 9.8) t^{2}

展开

8 t + (0.5) (- 9.8) t^{2} : 8 t - 4.9 t^{2}

- 13 = 8 t - 4.9 t^{2}

交换两边

8 t - 4.9 t^{2} = - 13

将

13

para o lado esquerdo

8 t - 4.9 t^{2} + 13 = 0

改写成标准形式

a x^{2} + b x + c = 0

- 4.9 t^{2} + 8 t + 13 = 0

使用求根公式求解

t_{1, 2} = \frac{- 8 \pm 8 ^{2} - 4 ( - 4.9 ) \cdot 13}{2 ( - 4.9 )}

8^{2} - 4 (- 4.9) \cdot 13 = 318.8

t_{1, 2} = \frac{- 8 \pm 318.8}{2 ( - 4.9 )}

将解分隔开

t_{1} = \frac{- 8 + 318.8}{2 ( - 4.9 )}, t_{2} = \frac{- 8 - 318.8}{2 ( - 4.9 )}

t = \frac{- 8 + 318.8}{2 ( - 4.9 )} : - \frac{- 8 + 318.8}{9.8}

t = \frac{- 8 - 318.8}{2 ( - 4.9 )} : \frac{8 + 318.8}{9.8}

二次方程组的解是:

t = - \frac{- 8 + 318.8}{9.8}, t = \frac{8 + 318.8}{9.8}

作图

流行的例子

x (x - 4.5) = 0

solvefor y,2.4(x+2)^2+(y-1.8)^2=1

so l v e f or y, 2.4 (x + 2)^{2} + (y - 1.8)^{2} = 1

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490 = - 250 t^{2} + 700 t