new way to make quadratic equations easy

08042021, 04:57 AM
Post: #9




RE: new way to make quadratic equations easy
I was surprised to learn that roots for quadratic equations could be solved using a slide rule, described in the manual for the Post Versalog:
Quote:If any quadratic equation is transformed into the form x^2 + Ax + B = 0, the roots or values of the unknown x may be determined by a simple method, using the slide rule scales. We let the correct roots be x_1 and x_2. By factoring, (x + x_1)(x + x_2) = 0. The terms x_1 and x_2 will be the correct values of x providing the sum x_1 + x_2 = A and the product of x_1 * x_2 = B. An index of the CI scale may be set opposite the number B on the D scale. With the slide in this position, no matter where the hairline is set, the product of simultaneous CI and D scale readings or of simultaneous CIF and DF scale readings is equal to B. Therefore it is only necessary to move the hairline to a position such that the sum of the simultaneous CI and D scale readings, or the sum of the simultaneous CIF and DF scale readings, is equal to the number A. 

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Messages In This Thread 
new way to make quadratic equations easy  Bill Duncan  07302021, 01:44 AM
RE: new way to make quadratic equations easy  Maximilian Hohmann  07302021, 11:42 AM
RE: new way to make quadratic equations easy  Ren  07302021, 01:46 PM
RE: new way to make quadratic equations easy  Namir  07312021, 04:22 AM
RE: new way to make quadratic equations easy  C.Ret  07312021, 10:19 AM
RE: new way to make quadratic equations easy  Albert Chan  08012021, 03:08 PM
RE: new way to make quadratic equations easy  Namir  07312021, 07:03 AM
RE: new way to make quadratic equations easy  Namir  08012021, 07:56 AM
RE: new way to make quadratic equations easy  Benjer  08042021 04:57 AM
RE: new way to make quadratic equations easy  C.Ret  08062021, 05:32 PM
RE: new way to make quadratic equations easy  Namir  08062021, 12:40 AM
RE: new way to make quadratic equations easy  Ren  08062021, 02:22 PM

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