Forward, right and up have positive connotations, backward, left and down have negative connotations. When it comes to directions, you do it the same way.
The LEGO cuboid represents the polynomial
f(x)=(x+0)(forward)(x+3)(right)(x-1)(down)
=x³ (blue cube)+3x² (red cuboid) -1x² (white cuboid)+ 3*-1*x (white cuboid)
=x³+2x²-3x
Half of its surface can be seen and equals the slope of the graph of the polynomial!!! We have 3 blue squares x², 2 red rectangles 3x, 2 white rectangles -1x, a white rectangle 3*-1
The slope of a function is called its first derivative f'(x)
Here we get 3x²+6x-2x-3, so f'(x)=3x²+4x-3
Polynomials are just building instructions for n-dimensional cuboids! In general, a polynomial looks like this:
f(x)=a1x^n+a2x^(n-1)+a3^(n-2)+...+a(n+1)x⁰. Half of its boundaries correspond to the slope a1. Geometrically, a1 stands for the number of cuboids or the proportion of a cuboid, a2 is the sum of the orthogonal sides, in our example 0+3-1=2, a3 is half of the areas, here 0*3+0*-1+ 3*-1=-3, a(n+1), the constant, corresponds to the total volume of the cuboids or the volume of a partial cuboid, here n=3, 0*3*-1=0 and at the same time is the intersection of the graph with the y-axis.
How to find the x-value of the vertex or middle inflection point of polynomials easily: Just divide a2 by n and a1 and change the sign, here a1=1, a2=2, n=3, so the inflection point (there is only one) is (-2/3;f(-2/3))
ALT II
The blue graph belongs to f(x)=1x³+2x²-3x and can be represented by the LEGO cuboid. Its zeros or roots are -3, 0, 1, its inflection point is (-2/3;-13/3).
The pink graph describes the slope of the blue graph and is its first derivative f'(x)=3x²+4x-3. At the inflection point, the slope is minimal. There are two points, where the slope of the blue graph is 0: These are the intersections with the x-axis.
The turquoise graph describes the slope of f'(x) and is called f''(x), here f''(x) equals 6x+4. Rectangles have four boundaries, edges. Two of them equal the first derivative, f.e.: g(x)=x², g'(x)=2x.
Edges have two points as boundaries. If h(x)=6x, h'(x)=6
The green graph describes the slope of the turquoise graph that is constant, so f'''(x)=6. Points have no boundaries, and no boundaries, no derivatives. So there is no f''''(x) here.
The area between the blue graph and the x-axis can be described by the purple curve, the antiderivative F(x) of f(x).
One cube represents only 1/4 of half the boundaries of a four-dimensional cube, so the antiderivative of f(x)=x³ equals F(x)=x⁴/4. One square represents just 1/3 of half the boundaries of a cube, so the antiderivative of g(x)=x² equals G(x)=x³/3. One edge represents half of half the boundaries of a square, so k(x)=1x and K(x)=x²/2. One point represents half the boundaries of an edge, so l(x)=1 and L(x)=1x.
The purple graph F(x), the antiderivative of f(x)=x³+2x²-3x equals x⁴/4+2x³/3-3x²/2+constant "c". The constant is important because when deriving information about the position of the function graph in the coordinate system is lost because it only describes the slope. You have to keep this in mind when antiderivatizing and therefore add c. The area between graph and x-axis depends on the position of the graph.
Hi fam,
have a fulfilling day!
#Januarty #Januarty2025 day 12, "tool"
This is an ingenious tool/toy: www.matheretter.de/rechner/gfplot
I used it for #Calculus of the #polynomial
f(x)=x³+2x²-3x
=(x+0)(x+3)(x-1), which can be represented by this LEGO cuboid!
#sharingisthenewlearning #PhotographyIsArt