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Prove that tan50°= 2tan10° + tan40° |
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Answer» Hope you understand it we have tan(a+b) = (tan a +tan b)/(1-tan a tan b) tan(40+10) = (tan40+ tan10)/(1-tan40tan10) tan50 = (tan40+ tan10)/(1-tan40tan10) tan50(1-tan40tan10)=tan40+ tan10 tan50-tan50tan40tan10 = tan40+tan10 and tan50 = tan(90-40) = cot40 => tan50-cot40tan40tan10 = tan40+ tan10 tan50-tan10 = tan40+ tan10 because cot40= 1/tan40 tan50 = tan40+2tan10 |
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