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Express tan22.5 using cos45
asked
Nov 27, 2018
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Express tan22.5 using cos45
Mathematics
middle-school
Melpomene
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Melpomene
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cos45 = cos(2*22.5) = (cos22.5)^2 - (sin22.5)^2 = (cos22.5)^2 * (1-(tan22.5)^2)
= (1 + cos45)/2 * (1-(tan22.5)^2)
Now, solve for tan22.5:
tan22.5 = sqrt(1 - 2cos45 / (1+cos45) )
Vivek Salve
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Dec 2, 2018
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Vivek Salve
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