SOLUTION: tanu=3/5 sin2u= cos2u= tan2u=

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Question 1206373: tanu=3/5
sin2u=
cos2u=
tan2u=
Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!

given:
tan%28u%29=3%2F5

=>opp%2Fadj=3%2F5 => opp=3 and adj=5

then
hyp=sqrt%283%5E2%2B5%5E2%29
hyp=sqrt%2834%29

now we have
sin%28u%29=3%2Fsqrt%2834%29
cos%28u%29=5%2Fsqrt%2834%29

use identities:
sin%282u%29=2cos%28u%29+%2Asin%28u%29
cos%282u%29=cos%5E2%28u%29+-+sin%5E2%28u%29
tan%282u%29=sin%282u%29%2Fcos%282u%29

sin%282u%29=2%285%2Fsqrt%2834%29%29+%2A%283%2Fsqrt%2834%29%29
sin%282u%29=2%28%285%2A3%29%2F34%29
sin%282u%29=15%2F17


cos%282u%29=%285%2Fsqrt%2834%29%29%5E2+-+%283%2Fsqrt%2834%29%29%5E2
cos%282u%29=25%2F34-+9%2F34
cos%282u%29=16%2F34
cos%282u%29=8%2F17


tan%282u%29=%2815%2F17%29%2F%288%2F17%29
tan%282u%29=15%2F8