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If sinA/sinB = √3/2 and cosA/cosB = √5/2 then tanA+tanB is equal to |
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Answer» sinA/sinB = √3/2 => sinA = (√3/2)sinB ...............(1) cosA/cosB = √5/2 => cosA = (√5/2)cosB ...............(2) Squaring and adding (1) and (2), 1 = (3/4)(sinB)2 + (5/4)(cosB)2 => 3(sinB)2 + 5(cosB)2 = 4 => 3(sinB)2 + 3(cosB)2+ 2(cosB)2 = 4 => 3{(sinB)2 + (cosB)2} + 2(cosB)2 = 4 => (cosB)2 = 1/2 => cosB = 1/√2 or -1/√2 => sinB = 1/√2 or -1/√2 => sinA = √3/(2√2) or -√3/(2√2) from (1) => cosA = √5/(2√2) or -√5/(2√2) from (2) Hence, tanA + tanB = √3/√5 + 1 |
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