Since 1 occurs in two places on the CI scale, one of them will always be on-scale. Scales are often «split» to get higher accuracy. The HP used the CORDIC (coordinate rotation digital computer) algorithm, which allows for calculation of trigonometric functions using only shift and add operations. The so-called «prayer wheel» is still available in flight shops, and remains widely used. For example, aligning the rightmost 1 on the C scale with 2 on the LL2 scale, 3 on the C scale lines up with 8 on the LL3 scale.
Owner Manuals Think of your product manual as the ultimate information resource for your Huffy® ride. One slide rule remaining in daily use around the world is the E6B. This is a circular slide rule first created in the 1930s for aircraft pilots to help with dead reckoning. The answer, 6, is read off the bottom scale where 3 is on the top scale. In general, the 1 on the top is moved to a factor on the bottom, and the answer is read off the bottom where the other factor is on the top. Inverse trigonometric functions are found by reversing the process. Trigonometric scales are sometimes dual-labeled, in black and red, with complementary angles, the so-called «Darmstadt» style. Freewheel bicycles refer to bikes in which the rear wheel continues to spin even when you are not pedaling.
This method facilitated the development of ever smaller scientific calculators. Most slide rules consist of three linear strips of the same length, aligned in parallel and interlocked so that the central strip can be moved lengthwise relative to the other two. The main disadvantages of circular slide rules are the difficulty in locating figures along a dish, and limited number of scales. Such slide rules have special scales which are useful in the particular field of application, in addition to the common ones.