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September 21, 2014

September 21, 2014

Posted by **olivia** on Wednesday, March 28, 2012 at 9:50am.

find sinA, sin2A, cos2A

- precal- PLEASE HELP! -
**Reiny**, Wednesday, March 28, 2012 at 11:16amcosA = 4/5 or opposite = 4, hypotenuse = 5

you should recognize the 3-4-5 triangle,

then sinA = 3/5

sin 2A = 2sinAcosA = 2(3/5)(4/5) = 24/25

cos 2A = cos^2 A - sin^2 A

= 16/25 - 9/25 = 7/25

- precal- PLEASE HELP! -
**olivia**, Sunday, April 1, 2012 at 10:21pmthank you.

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