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It supports mathematical functions (including trigonometric functions).
Current location：Mathematical operation > History of Mathematical Computation > Answer
Overview: 1 questions will be solved this time.Among them
☆1 equations
[ 1/1 Equation]
Work: Find the solution of equation 90 = 5/(1+y)+5/(1+y)2+105/(1+y)3 .
Question type: Equation
Solution:Original question:
| 90 | = | 5 | ÷ | ( | 1 | + | y | ) | + | 5 | ÷ | ( | 1 | + | y | ) | × | 2 | + | 105 | ÷ | ( | 1 | + | y | ) | × | 3 |
| Multiply both sides of the equation by: | ( | 1 | + | y | ) |
| 90 | ( | 1 | + | y | ) | = | 5 | + | 5 | × | 2 | + | 105 | × | 3 |
| 90 | × | 1 | + | 90 | y | = | 5 | + | 5 | × | 2 | + | 105 | × | 3 |
| 90 | + | 90 | y | = | 5 | + | 10 | + | 315 |
| 90 | + | 90 | y | = | 330 |
Transposition :
| 90 | y | = | 330 | − | 90 |
Combine the items on the right of the equation:
| 90 | y | = | 240 |
The coefficient of the unknown number is reduced to 1 :
| y | = | 240 | ÷ | 90 |
| = | 240 | × | 1 90 |
| = | 8 | × | 1 3 |
We obtained :
| y | = | 8 3 |
Convert the result to decimal form :
| y | = | 2.666667 |