Sharp EL9900C EL-9900C - Page 58

Chapter 3: Basic Calculations - Basic Keyboard 6 nCr Returns the total number of combinations for selecting "r" item out of "n" items. nCr = n! r!(n - r)! Example • How many different groups of 7 students can be formed with 15 students? 1 5 M C 6 7 E 7 ! Returns a factorial. Example • Calculate 6 × 5 × 4 × 3 × 2 × 1. 6 M C 7 E D CONV CONV sub-menu items are to be used when converting a number in decimal form (degrees) to a number in sexagesimal form (degrees, minutes, seconds), or vice versa. Sexagesimal and Degree System The "base 60" sexagesimal system, as well as the minutessecond measurement system, was invented by the Sumerians, who lived in the Mesopotamia area around the fourth millennium B.C.(!) The notion of a 360 degrees system to measure angles was introduced to the world by Hipparchus (555-514 B.C.) and Ptolemy (2nd cent. A.D.), about 5000 years later. We still use these ancient systems today, and this calculator supports both formats. 1 →deg Takes a number in sexagesimal form, and converts it into a decimal number. Example • Convert 34° 56' 78" to degrees. 3 4 M E 1 5 6 M278 M 3 MD1 E 48