Futuremedstudent? Posted July 14, 2008 Report Share Posted July 14, 2008 So I finally started to review physics and I got as far as vectors when I realized I have no idea how to calculate trig functions (ie sin/cosin) without a calculator. I know S=O/h, T=O/A, and C= A/H but what I don't know is how to calculate sin(O/H) without a calculator. Do they just leave the answer with the sin/cos in it?? Or is there some trick to give a rough estimate of the answers? Thanks! Link to comment Share on other sites More sharing options...
supafield Posted July 14, 2008 Report Share Posted July 14, 2008 there are tricks... basically just know a few major angles and then your fine... any odd angle you'd estimate between the values you know.... So for Sin and Cos I Remember first ( S )in is ( S )imple and ( C ) os is ( C ) omplex when setting up this chart I'll show you.... all that means is since sin is simple so it starts at 0 and counts up while cos is complex so it starts at 4 and counts down Angle-----Sin-----Cos 0----------0-------4 30--------1-------3 45--------2-------2 60--------3-------1 90--------4-------0 Once you've set that chart up you the take any of the value and take the square root of the number Angle Sin Cos 0---------0--------------2 30--------1------------root 3 (1.7) 45-----root 2 (1.4)----root 2 (1.4) 60-----root 3 (1.7)------1 90---------2 -------------0 The only piece of memorization you really need for this system is that root 3 is approximately 1.7 and root 2 is ~ 1.4 The final step you divide all the values by 2 Angle Sin Cos 0---------0--------1 30-------1/2-----~0.85 45------~0.7----~0.7 60------~0.85-----1/2 90---------1---------0 And there you have it... your rarely see an angle outside of these but for instance if you got needed to calculate Sin50 you know it's slightly more than 0.7 so you take 0.75. Hope this helps Link to comment Share on other sites More sharing options...
dan0105 Posted July 18, 2008 Report Share Posted July 18, 2008 I was going to say memorize those triangles, but that chart is even easier, that's a clever trick... Link to comment Share on other sites More sharing options...
HBP Posted July 18, 2008 Report Share Posted July 18, 2008 I was going to say memorize those triangles, but that chart is even easier, that's a clever trick... You should thank EK. Link to comment Share on other sites More sharing options...
supafield Posted July 18, 2008 Report Share Posted July 18, 2008 You should thank EK. TPR for me... Link to comment Share on other sites More sharing options...
whale.of.a.time Posted July 22, 2008 Report Share Posted July 22, 2008 very helpful, thanks! Link to comment Share on other sites More sharing options...
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