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If point a (2,0) B (0, b) (a > 0, b > 0) and point m (3,2) are collinear, then the minimum value of a + B is A (a, O)... I'm wrong~
Let the equation of the line AB be (intercept form) x / A + Y / b = 1m on the line ﹥ 3 / A + 2 / b = 1 ﹥ a + B = (a + b) (3 / A + 2 / b) = 5 + 3B / A + 2A / b ≥ 5 + 2 · radical (3b / a · 2A / b) = 5 + 2 · radical
A and B walk in the same direction. A's speed is 3km per hour, B's speed is 5km per hour. If a passes by a at 12 noon and B passes by a at 2 pm, B will catch up with a at () PM, and the distance to a is () km
2×3÷（5-3）
=6÷2
=3 hours
5 × 3 = 15 km
A and B walk in the same direction. A's speed is 3km per hour, B's speed is 5km per hour. If a passes a at 12 noon and B passes a at 2 pm, B will catch up with a at (5) PM, and the distance from the place to a is (15) km
A and B are walking in the same direction from two places 5km apart on the same road. A's speed is 5km / h, and B's speed is 3km / h. A takes a dog with him. When a pursues B, the dog pursues B first, then returns to meet a, and then returns to chase B It is known that the speed of the dog is 15km / h. The total distance of the dog in this process is calculated
Suppose the time for a to catch up with B is x hours, then: 5x = 3x + 5, the solution is: x = 2.5 15 × 2.5 = 37.5km. A: the total distance of dog running is 37.5km
The distance between a and B is 25km, and they run towards each other at the speed of 4.5km/h and 5.5km/h respectively. At the same time, the dog with a runs to B at the speed of 7.5km/h. When the dog meets B, it immediately turns around and runs to A. when it meets a, it runs to B. when the dog arrives at B, it immediately runs to a Until a and B meet, find out the distance the dog has taken, and solve the equation
The distance the dog runs
=【25÷（4.5+5.5）】×7.5
=2.5×7.5
=18.75 km
RELATED INFORMATIONS
- 1. A and B are 15km apart, and they are walking at the speed of 2.5km/h and 5km / h respectively, while the dog with a is 7.5km/h To B, the dog runs to a immediately after meeting B, runs to B when meeting a, and runs to a immediately after meeting B Until a and B meet, find the dog's distance. Use the equation solution
- 2. A and B are moving in the same direction on the road at a constant speed. A's speed is 3 km / h, and B's speed is 5 km / h. A passes through place a at 12 noon, and B passes through place a at 2 pm. What time can b catch up with a in the afternoon? How far is it from ground a?
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