I saw a dude start a campfire once by pissing on some kindling. I was amazed, and sort of stoned, and asked him what the secret was.
Late stage gonorrhea.
More likely elemental sodium placed on the kindling.
Thanks to Tad I just bought a slide ruler...
I do agree with him that the overuse of calculators, makes the brain weaker atalgebra, the actual stuff we need on day to day tasks. I don't care aboutlogsand calculus, but basic algebra you should be able to do in your brain in an instant, for example, adding numbers between 1 and 100, without a calculator.
Good for you - hopefully a nice Versalog - unfortunately a lot of overinflated rulers for sale on ebay by shitty sellers who don't understand that no one is going to buy a slide rule with a broken cursor or in otherwise crappy condition.
And everyone should care about logarithms even for algebra.
Let's take TheBeagle's example here:
That's a good idea up until high school, but you really expect kids to do logs, exponents, long division,quadratic formula, etc....by long hand? So they could maybe get through 3 problems during a one hour test. Brilliant.
Let's say you want to solve a quadratic equation in less than the one hour you're given on your test and all you've got is your trusty slide rule. Fortunately for you the logarithmic super powers of your slide rule can help you solve that quadratic. From the Versalog manual:
Basic quadratic equation is of the form: x^2 + Ax + B = 0. Quadratics have two roots: -r1 and -r2. The properties of the two roots are such that r1*r2=B and r1+r2=A. For example the x^2+2x+1=0 has the form (x+1)(x+1)=0 and the -r1 and -r2 are both 1. r1*r2=1 and r1+r2=2.
To solve a quadratic with the slide rule you set the index* of C to the value of "B" on the D scale. This represents r1*r2 for any setting of the indicator for the D & CI scale (check this on one of the virtual slide rules with a CI/D scale. Set left index of C to 15 every combination of D&CI are factors of 15 (or 150/1500/Etc) - for example 2 on D is across from 7.5 on CI, 4 on D is across from 3.75).
Now move the hairline until you discover two numbers whose sum is equal to A - may take a minute or two and you have to do the addition in your head (oh noes!) But once you find those two numbers you have your quadratic roots.
Example from V2 book cause I'm being rationally lazy right now: x^2+10x+15=0. Set left index of C to 15 on D. Move hairline until CI+D=10. This occurs at 8.15 on CI and 1.84 on D - both are positive because A and B are positive. Roots are -8.15 and -1.84 (which is 9.99 within precision of a slide rule at that end of the slide)
So (a) no it won't take one hour to do a quadratic equation and (b) slide rules are infinitely cooler than scientific/graphing calculators.
*right or left depending on the value of B
Note: I am only recommending slide rules for 7-12th grades and early college to help students properly learn math. Despite khalid's assertion, no I don't think slide rules are coming back (unfortunately)...
