Hello,

Remember that

So with the information given, calculate and and substitute in the formula you're given for

it doesn't matter :PThe cos of b, if you notice, is negative.

makehow do I find tan(a + pi)?

makewhat's cos (a + pi/3)?

make in the sin(x-y) formula.and what's sin (pi/6 - a)?

Now, for these last 3 values, you have to know specific values of trigonometric functions, at some points.

They're "listed" here : http://everobotics.org/projects/robo...UnitCircle.gif