How Many Formulas?
Date: 11/25/2002 at 19:42:46 From: Rebecca Subject: Math Hey, I have a question. I am in pre-algebra and I just want to know, How many formulas do you actually have to learn? And does it ever get easy? Another questian. I am planning on taking PRE ALG, alg1, and then BUSINESS MATH (not alg 2). Is this going to affect me in any way in my life? Will I be dumb? Thanks, Rebecca
Date: 11/26/2002 at 01:40:37 From: Doctor Ian Subject: Re: Math Hi Rebecca, There's no limit to the number of formulas in math, because people are making up new ones all the time. However, you don't have to know very many of them. Here are just about all the formulas that I've memorized: 1. area of a rectangle = length * width 2. area of a circle = pi * radius^2 3. volume of a prism = area of base * height 4. sin^2 + cos^2 = 1 (This is really just a version of the Pythagorean Theorem.) 5. The quadratic formula, -b +/- sqrt(b^2 - 4ac) x = ---------------------- whenever ax^2 + bx + c = 0 2a 6. The derivative of e^x is e^x. 7. The derivative of ax^n is anx^(n-1). Along with some definitions (e.g., exponents, and the sine, cosine, and tangent functions), I think that's about it. (Don't worry too much if you don't understand what they all mean. The important point is that there aren't very many of them.) There are lots more formulas than this. But if when you learn about a new formula, you make sure that you _understand_ why it works, then you don't have to remember it, because you can figure it out again later if you need it. (For example, you can turn any parallelogram into a rectangle by cutting a piece from one side and moving it to the other. So I can figure out that the area of a parallelogram is the same as the area of the rectangle that has the same base and height. And you can make any triangle by cutting a parallelogram in half. So I can figure out that the area of a triangle is half the area of the corresponding parallelogram, which is the same as the area of the corresponding rectangle. See how it works?) As for your other question, not taking algebra won't make you 'dumb'. But it will make it somewhat easier for other people to take advantage of you by using statistics, graphing tricks, and so on. And you may find later that you're unable to pursue certain careers because you won't know enough math to learn about them. But certainly there are lots of happy, productive, well-adjusted, and perfectly intelligent adults who couldn't solve an algebra problem if their lives depended on it. Fortunately for them, hardly anyone's life ever depends on it. Does this help? - Doctor Ian, The Math Forum http://mathforum.org/dr.math/
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