Question 220645
Find the exact value of tan 15 
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[tan(15) = tan(60-45) 
= [tan(60)-tan(45)]/[1+tan(60)*tan(45)]
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= [sqrt(3)-1]/[1+sqrt(3)*1]
Multiply numerator and denominator by 1-sqrt(3) to get:
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= [-(1-sqrt(3))^2]/(1-3)
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= (1-2sqrt(3)+3)/2
= (4-2sqrt(3)]/2
= (2-sqrt(3))
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Cheers,
Stan H.