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Co-ordinate Geometry JEEMain(ref. attachment) |
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Answer» ong>Answer: 21. Step-by-step explanation: Let, A ----> (2,-3) B ----> (-5,6) Point on Y AXIS , P ----> (0, y ) M1 : M2 : : l : m. Assume, m = 1. So, M1 : M2 : : l : 1. P (0, y ) -----> { [(l )(-5) + (1 )(2 )] / [ l + 1 ] } , { [(l )(6 ) + (1 )(-3 )] / [ l + 1 ] } ------> { [-5L + 2] / [ l + 1 ] } , { [6l - 3] / [ l + 1 ] } Comparing both sides, 0 = [-5l + 2] / [ l + 1 ] -5l + 2 = 0 -5l = -2 l = -2/-5 = 2/5. So, M1 / M2 = l / 1 = (⅖)/1 = 5/2 So, M1 : M2 : : 5 : 2 i.e., l = 5 m = 2. To find, l² - m² = 5² - 2² = 25 - 4 = 21. P.S. : I'm in class 10. So, I'm not sure if it is correct. We're currently studying Coordinate geometry at school. So, I tried to solve it with that knowledge only. Hope this helps !!!! You're PREPARING for JEE ????!!!! OMG... Anyway, best of luck...! You can crack it !!!! |
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