Power Algorithm

If the powers are integral, use the Serial Multiplication algorithm below.

If they are not integral, you must use the formula x^y = e^[y*ln(x)], and use the ln(x) and e^x algorithms.

**********

Serial multiplication (A*B*C*D...)

**********

Serial multiplication without clearing (method 1):

5*7*12*36

First, enter 5 in SR, and crank 7 times to get 35 in RR

Now enter 12 in SR. Since we want to get 35 *twelve* times, and we already have 35 *one* time in the RR, we need (12-1) *more* 35s. So decrease 12 by one in the SR to 11.

Now so you don't forget how many times to turn, move the registers so the leftmost digit of current result (35) lines up with rightmost digit of SR (11). See a 3, crank three times. Move one to the right, see a 5, crank 5 times. Now you have 420.

Enter (36-1)=35 in SR. Line up the 5 with the 4 in 420. Crank 4 times, twice in the next position, 0 times in the last position. Now you have 15120.

**********

Serial multiplication without clearing (method 2):

5*7*12*36

First, enter 5 in SR, and crank 7 times to get 35 in RR

Now enter 11.9 in SR. Since we want to get 35 *twelve* times, and we already have 35 *one* time in the RR, we'll move the decimal one to the left. Now we have 35 *0.1* times, and we need (12-0.1) *more* 35s. So decrease 12.0 by 0.1 in the SR to 11.9.

Now so you don't forget how many times to turn, move the registers so the leftmost digit of current result (35) lines up with rightmost digit of SR (11.9). See a 3, crank three times, UNTIL THE DIGIT GOES TO ZERO. Move one to the right, see a 5, crank 5 times, UNTIL THE DIGIT GOES TO ZERO. Now you have 420. Sending the digit to zero is the advantage of this method over method 1, you don't have to remember how many times to crank. However, you do use up more decimal places.

Enter (36-0.1)=35.9 in SR. Line up the 9 with the 4 in 420.0. Crank 4 times (UNTIL ZERO), twice in the next position, 0 times in the 3rd position. Now you have 15120.00.


Edit Text of this page (last edited May 10, 2004 by ulugh.nationwide.com)
Find Page by browsing or searching
Brought to you by Curta.org