Sin, Cos, Tan with a calculator

1. Sin, Cos, Tan with a calculator If you are finding the sin, cos, tan of an angle that is not a special case (30, 60, 45) you can use your calculator to approximate its value to 4 decimal places Make sure your calculator is in the proper mode (degrees or radian) based on the problem you are solving There is a sin, cos, tan button on your calculator – you hit that button and then put the angle your are working with in parenthesis

2. Sin, Cos, Tan with a calculator If you are working with Radians make sure that you use the button Always round to 4 decimal places if it is not an exact answer Your calculator will find the sin, cos, tan of any angle – however if it is a special case angle (30, 60, 45) your are expected to use your chart to put down the EXACT answer (Fraction)

3. Examples Find the sin 65º Make sure your calculator is in degrees (hit the mode button – then the 3rd selection down is radian or degrees, highlight the one you want and hit enter, then hit 2nd mode to go back to the main screen) Hit the sin button and then 65 to get: sin(65) = .906307787 (round to 4 decimals) sin(65) = .9063 (rounded)

4. Examples Find the tan Make sure your calculator is in radians Hit the tan button and then (2 /7) to get: tan(2 /7) = 1.253960338 (round to 4 decimals) tan(2 /7) = 1.2540 (rounded) Remember that to get the you hit 2nd and then the ^ key

5. Inverse Trig Functions If we start out with the trig value we can find the angle that it comes from by using the inverse trig functions For the special angles (30, 60, 45) you can use the charts, for all other angles we will use the calculator You will see these written two different ways: Our book uses arcsin, arccos, arctan – your calculator uses the following:

6. Inverse Trig Functions If you see something written as arcsin(.2345) it is asking you to find the angle that has a sin value of .2345 For something like that (arcsin(.2345)) we will use the calculator If we are asked something like arcsin(1/2) we need to use the chart

7. When to use the charts If you see the following look at your charts to get the angles: The only decimal you will use the chart for is .5 which is equal to

8. Examples Find the arctan for an angle in both radians and degrees You use the chart because this is one of the special angles Looking in the degree chart you can see that 30º has this value for its tan Looking in the radian charts you can see that has this value for its tan

9. Examples Find the arcsin(.75) in degrees and radians Hit 2nd sin on your calculator to get arcsin or so you can get an angle – you will need to do this in both radians and degrees Radians