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How many points (x,y) with integral co-ordinates are there whose distance from (1,2) is two units ?1.one 2. two 3. three 4. four |
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Answer» Correct option: (4) four Explanation: (x - 1)2 + (y - 2)2 = 4 It is possible only Case I (x - 1)2 = 0 and (y - 2)2 = 4 => x = 1 and y = 0 , 4 so the points are (1 , 0) , (1 , 4) Case II (x - 1)2 = 4 and (y - 2)2 = 0 => x = 3 , - 1 and y = 2 so the points are (3 , 2) , (3 , - 1) So total four points are |
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