If the rational number a is equal to its reciprocal and the rational number b is equal to its opposite, then a2009+b2009 is equal to () A.1 B.-1 C.±1 D.2

If the rational number a is equal to its reciprocal and the rational number b is equal to its opposite, then a2009+b2009 is equal to () A.1 B.-1 C.±1 D.2

The rational number a is equal to its reciprocal,
A =±1,
The rational number b is equal to its opposite number,
B =0,
When a=1, b=0, a2009+b2009=12009+02009=1,
When a=-1 and b=0, a2009+b2009=(-1)2009+02009=-1,
In summary, a2009+b2009 equals ±1.
Therefore, C.

Say what each percentage means. 1. According to the results of the 7th National Reading Survey, the reading rate of Chinese people aged 18~70 in 2009 was 50.1%. 2. In 2009, the air quality of Hefei City was significantly improved as compared with that of the previous year. The annual air quality was excellent and the excellent days were 317 days, and the excellent rate was 86.8%. 3. The population of China accounts for about 22% of the world population, and the energy consumption accounts for about 10% of the world.

1. The number of reading books of Chinese nationals aged 18~70 accounts for 50.1% of the total number of Chinese nationals aged 18~70.
2. Excellent air quality and excellent days account for 86.8% of the total days of the year
3. The ratio of Chinese population to the world population is 22:100, and the energy consumption accounts for about 10% of the world's energy consumption.