Calculus Midoriさんのイラストまとめ

>Second trapezoid. h=55, a=15, b=27
>A=(1/2)(55)(15+27)=1,155in^2
>Add them up and the surface is 1617in^2

>The area formula for trapezoids is A=(1/2)(h)(a+b), where h is the height, and a and b are the base lengths.
>For the first trapezoid, as pictured, h=22, a=15, b=27
>A=(1/2)(22)(15+27)=462in^2
>Yes, this is all in inches.

>Asunaro had implemented standard and fashionably comfortable coffins, I can testify. In fact, I even have some of the blueprints.
>When calculating surface, we want to break it down to recognizable polygons. Here, we can see two isosceles trapezoids.

>How's that for today? Quite the mouthful, I know. And I barely scratched the surface! I'll take a break for now, don't miss me too much.

>(x^2+2x), GCF is x. Pull it out and you get x(x+2)
>(-3x-6), GCF is -3. Pull it out and you get -3(x+2)
>Now you have x(x+2)-3(x+2). You can now pull out the (x+2) from both of these group to get the factored version: (x-3)(x+2)

>With x^2+2x-3x-6, we start grouping. I'll make it easier to read by separating it into 2 groups: (x^2+2x)+(-3x-6).
>Once again, equivalent expressions. We will now pull out the GCF (greatest common factor) from both of these groups.

>Let the read thread of fate activate! 3 and 2, what a lovely pair.
>We break the expression down from x^2-x-6 to x^2+2x-3x-6. Both expressions are equivalent.
>Don't complain about how we added like terms only to separate them, these are both crucial steps.

>We need to find a pair of factors (1 and 6 or 2 and 3), which adds up to b, -1, where the larger factor takes the -.
>With 1 and 6, 6 will take the -, while 1 takes the +. 1 + (-6) = -5. That is not -1.
>2 and 3, 3 takes -, 2 takes +. 2 + (-3) = -1. We found a pair!

>a=1, b=-1, c=-6
>- c, larger factor will take -.
>When I have been speaking about factors, I mean it about the factors of the constant, c. c=6 here, so we need to find factors of 6.
>1, 2, 3, 6

>I hope the explanation's enough. I'm not going to repeat myself, so brand this in your memory. Or, you know, check out my super handy dandy pinned to refer to older lessons!
>At last, we can go back to our original example, x^2-x-6.