x+1 двенадцатая=7двенадцатых-1седьмая

x+1 двенадцатая=7двенадцатых-1седьмая
- Предмет:
  Математика
- Автор:
  pyscho
- 6 лет назад

Ответы 1

12 = 2 * 2 * 3 7 = 1 * 7НОК (12 и 7) = 2 * 2 * 3 * 7 = 84 - наименьшее общее кратное (общий знаменатель)84 : 12 = 7 - доп. множитель для 1/12 и 7/1284 : 7 = 12 - доп. множитель для 1/7--------------------------------------------------х + 1/12 = 7/12 - 1/7х = 7/12 - 1/7 - 1/12х = 49/84 - 12/84 - 7/84х = 30/84х = 5/14
- Автор:
  fletcher
- 6 лет назад
- 0
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Electric shock
In all manual arc welding operations, the principal risk is from electric shock, most likely from contact with bare live parts of the welding circuit. The arc voltage is within the range 10 to 40 V, but, as the voltage required to strike the arc may be substantially higher, power sources have an open circuit voltage (OCV), typically up to 80V. Although these voltages appear low compared with the 230V domestic mains supply, work by the International Electrotechnical Commission shows that only voltages below 50V AC or 120V DC are unlikely to be dangerous to healthy people in a dry working environment. In other conditions such as restricted conducting locations or wet surroundings, potentials of 80V AC have been the cause of fatal electric shocks. Devices are available which reduce the open circuit voltage when welding is not being carried out. These voltage reduction devices (VRD) should meet the requirement of BSEN 60974-1.
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There is an increased risk of stray currents when welding on structures which have an inherent connection to earth such as ships or pipelines. There could be an unacceptable indirect current return path with damage to conductors if, for example, the current return lead is detached and the circuit becomes open. The recommendations for the electrical distribution systems and earth connections in various situations are described in HS(G) 118.
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x+1 двенадцатая=7двенадцатых-1седьмая

Ответы 1

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