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受欢迎的代数 >

25=-4.9t^2+20t+20

解答

25 = - 4.9 t^{2} + 20 t + 20

解答

t = \frac{5 ( 20 - 302 )}{49}, t = \frac{5 ( 20 + 302 )}{49}

+1

十进制

t = 0.26753 \dots, t = 3.81409 \dots

求解步骤

25 = - 4.9 t^{2} + 20 t + 20

在两边乘以

10

250 = - 49 t^{2} + 200 t + 200

交换两边

- 49 t^{2} + 200 t + 200 = 250

将

250

para o lado esquerdo

- 49 t^{2} + 200 t - 50 = 0

使用求根公式求解

t_{1, 2} = \frac{- 200 \pm 20 0 ^{2} - 4 ( - 49 ) ( - 50 )}{2 ( - 49 )}

20 0^{2} - 4 (- 49) (- 50) = 10302

t_{1, 2} = \frac{- 200 \pm 10 302}{2 ( - 49 )}

将解分隔开

t_{1} = \frac{- 200 + 10 302}{2 ( - 49 )}, t_{2} = \frac{- 200 - 10 302}{2 ( - 49 )}

t = \frac{- 200 + 10 302}{2 ( - 49 )} : \frac{5 ( 20 - 302 )}{49}

t = \frac{- 200 - 10 302}{2 ( - 49 )} : \frac{5 ( 20 + 302 )}{49}

二次方程组的解是:

t = \frac{5 ( 20 - 302 )}{49}, t = \frac{5 ( 20 + 302 )}{49}

作图

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