1. Trig functions are done in PIC's patented method which uses less space but requires more cursor movements.
2. A copy of the instructions for use can be found here.
3. In the detailed image of the differential sin scale we show the value sin 30°. The 30° in the S scale is aligned with 30 on the D scale and the answer, 0.5, is read against the 10 of the D scale.
4. In the detailed image of the differential inverse sin scale we show the value sin^-1 0.5. The 0.5 in the IS scale is aligned with 0.5 on the D scale and the answer, 30°, is read against the 1 of the D scale. Note that in both of these examples there is the need to understand where to place the decimal point.
5. For an article on the "differential" trig scales see the article by John Mosand (Two Unusual Types of Trigonometric Scales) by John Mosand in the Journal of the Oughtred Society, Vol. 9, No. 1, Spring 2000.

Front view

Detail - front left

Differential sin scale

Differential inverse sin scale