## Wndsn Quadrant Telemeter Tutorials

*Making the most out of our graphical telemetry computers.*

Like with many complex instruments, there are multiple ways to solve certain problems and to measure the required inputs. Combining the various functions leads to a multitude of advanced uses.

### Computing Sine (and Cosine)

It is often necessary to find the sine or cosine of an angle when performing a calculation. Finding the rough figure for sine or cosine given an angle is easy using a sine quadrant.

Two half-circle arcs, one centered on the sine scale, one centered on the cosine scale, can be used in conjunction with the sine and cosine scales as a method of converting angles.

If you haven't done it yet, now is a good time to install a cursor on the string. (Latin for 'runner,' a cursor is the name given to the transparent slide engraved with a hairline that is used for marking a point on a slide rule and which we are using on our quadrant to store a value and move it to a different scale.)

#### What's the sine of 36°?

- Pull the string taut over the angle.
- Move the sliding knot on the string to rest directly on the sine arc.
- Once the marker is in place, rotate the string to the left-hand sexagesimal scale, note the
**red arrow**. - The left-hand scale shows: sin(36°) ≈ 35/60 = 0.58

Conversely, to find the angle represented by a given sine, the process works in reverse.

Computing cosine is done in a similar manner. Notice that as the string is rotated from 0° to 90° the sine varies from 0/60 (0) to 60/60 (1) with the cosine changing in reverse from 1 to 0, as expected.