HP 39g hp 39g+ (39g & 40g)_mastering the hp 39g+_English_E_F2224-90010.pdf - Page 253

TRUNCATE(num) This function operates similarly to the ROUND function, but simply drops the extra digits instead of rounding up or down. It is somewhat similar in effect to the FLOOR function but the TRUNCATE function will work to any number of decimal places or significant figures instead of always dropping to the nearest lower integer value. Eg. TRUNCATE(3405.6375,-6) = 3405.63 TRUNCATE(32.889,1) = 32.8 See also: INT, FLOOR, CEILING, ROUND,FRAC XPON(num) This function returns the exponent (indicial part) when transformed into scientific notation of the number you feed it. It would be used with the XPON function, which returns the power part of the number when in scientific notation. Eg. Change 487 ⋅ 23 into scientific notation to get 4 ⋅8723×102 . MANT(487.23) = 4.8723 XPON(487.23) = 2 Change 0 ⋅ 0005087 into scientific notation to get 5⋅ 087 ×10−4 . MANT(0.0005087) = 5.087 XPON(0.0005087) = -4 This function could be of use to you if you are just learning scientific notation, but is of more use to people writing programs. A normal user would just look at the number and see the answer, but a programmer would not know in advance what number was going to be used and so might use MANT and XPON. See also: MANT 253