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November 28, 2014

November 28, 2014

Posted by **jeethu** on Tuesday, January 15, 2013 at 12:19am.

- maths -
**Steve**, Tuesday, January 15, 2013 at 12:08pmin QII, cosy is negative

cosx = -4/5

siny = 5/13

now, just plug in the formulas. for example

sin(x+y) = sinx*cosy+cosx*siny

= (3/5)(-12/13)+(-4/5)(5/13)

= -36/65 - 20/65

= -56/65

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