Mastering Graph Transformations: $r(x)$ To $g(x)$ Unveiled

by Admin 59 views
Mastering Graph Transformations: $r(x)$ to $g(x)$ Unveiled

Unraveling the Magic: What Are Graph Transformations Anyway?

Hey guys, ever looked at two seemingly similar math equations and wondered how one graph morphs into another? It's like giving your graph a total makeover, and that's exactly what graph transformations are all about! These are some of the coolest and most fundamental concepts in algebra and pre-calculus, allowing us to predict and understand how functions move, stretch, or flip on a coordinate plane without having to plot a zillion points. Think of them as special effects for your mathematical functions. We're not just drawing lines; we're giving them personality and motion! There are a few main types of transformations we typically encounter: we've got our shifts, where the graph slides up, down, left, or right; our stretches and compressions, which make the graph taller/narrower or shorter/wider; and then our reflections, where the graph flips over an axis, like looking in a mirror. Mastering these concepts is super important because functions, especially our parabolas, which are the stars of today's show, pop up everywhere – from predicting the trajectory of a thrown ball to designing satellite dishes. Today, we're diving deep into a specific pair of quadratic functions: r(x)=βˆ’(x+6)2+1r(x)=-(x+6)^2+1 and g(x)=βˆ’9(x+6)2+9g(x)=-9(x+6)^2+9. These equations might look a bit intimidating at first glance, but I promise you, by the end of this, you'll be able to confidently explain the exact graph transformation that turns r(x) into g(x). We're going to break down every single component, understand what it means for the graph, and then piece it all together to reveal the grand transformation. So buckle up, because understanding these transformations isn't just about passing a math test; it's about gaining a deeper intuition for how mathematical relationships play out visually, which is a powerful skill, my friends.

Meet Our Functions: r(x)r(x) and g(x)g(x) Up Close

Alright, let's get to know our main characters, r(x) and g(x). Both of these beauties are quadratic functions, which means their graphs are parabolas. If you've ever dealt with an x^2 term, you've likely met a parabola. They're those lovely U-shaped (or upside-down U-shaped) curves that are symmetrical around a central line. Our functions are given in a super helpful format called vertex form: y=a(xβˆ’h)2+ky = a(x-h)^2 + k. This form is a golden ticket because it immediately tells us a few critical things about the parabola: (h, k) is its vertex (the highest or lowest point), and a tells us if it opens up or down, and how wide or narrow it is. Let's dissect r(x) first: r(x)=βˆ’(x+6)2+1r(x)=-(x+6)^2+1. Comparing this to the vertex form, we see that a=βˆ’1a = -1, h=βˆ’6h = -6 (because it's x-h, so x-(-6) gives us x+6), and k=1k = 1. This immediately tells us that the vertex of r(x) is at (βˆ’6,1)(-6, 1). The negative sign for a (i.e., a=-1) is a crucial piece of information; it means our parabola opens downwards, like a sad face. The (x+6) inside the parentheses indicates a horizontal shift 6 units to the left from the standard x^2 parabola. And finally, the +1 at the end signifies a vertical shift 1 unit upwards. So, r(x) is essentially a standard parabola, shifted left by 6, flipped upside down, and then bumped up by 1. Now, let's turn our attention to g(x)$: $g(x)=-9(x+6)^2+9$. Again, this is a quadratic function in vertex form. Here, we have $a = -9$, $h = -6$, and $k = 9$. So, the *vertex* of g(x)is at $(-6, 9)$. Notice something *super interesting* right off the bat? The(x+6)^2` part is identical in both `r(x)` and `g(x)`! This is a massive clue, guys. It means that whatever transformation occurred, it didn't involve an additional horizontal shift between `r(x)` and `g(x)`. Both parabolas have their axis of symmetry at `x = -6`. The negative `a` value (now `a=-9`) still means it opens downwards, but the `9` tells us something very specific about its vertical stretch or compression. The `+9` at the end means it's vertically shifted up by 9 units. So, we've got two upside-down parabolas, both centered horizontally at `x=-6`, but their vertices and overall shape seem different. This careful inspection sets the stage for uncovering the exact transformation.

The Big Reveal: Unmasking the Transformation

Okay, folks, this is where the aha! moment happens. We've introduced our two functions, r(x)=βˆ’(x+6)2+1r(x)=-(x+6)^2+1 and g(x)=βˆ’9(x+6)2+9g(x)=-9(x+6)^2+9. Now, let's get down to the nitty-gritty: what exactly did we do to r(x) to transform it into g(x)? We need to look closely at the differences, especially the numbers that are not inside the (x+6) part. Let's rewrite r(x) slightly to highlight its components: r(x)=βˆ’1imes(x+6)2+1r(x) = -1 imes (x+6)^2 + 1. And g(x) is g(x)=βˆ’9imes(x+6)2+9g(x) = -9 imes (x+6)^2 + 9. What do you notice when you compare these two side-by-side? The (x+6)^2 term is exactly the same, which, as we mentioned, tells us there's no new horizontal shift. However, the coefficient of (x+6)^2 changed from -1 to -9. And the constant term at the end changed from +1 to +9. Do you see a pattern connecting these changes? It looks like every single term in r(x) has been multiplied by the same number to get the corresponding terms in g(x). Let's test this theory. If we assume that g(x) is simply r(x) multiplied by some constant K, then we'd have g(x)=Kimesr(x)g(x) = K imes r(x). Substituting r(x) into this equation: g(x)=Kimes[βˆ’(x+6)2+1]g(x) = K imes [-(x+6)^2 + 1]. Now, using the distributive property, we multiply K by each term inside the brackets: g(x)=Kimes(βˆ’(x+6)2)+Kimes(1)g(x) = K imes (-(x+6)^2) + K imes (1). This simplifies to g(x)=βˆ’K(x+6)2+Kg(x) = -K(x+6)^2 + K. Now, let's compare this general form to our specific g(x): g(x)=βˆ’9(x+6)2+9g(x) = -9(x+6)^2 + 9. By matching the coefficients, it becomes incredibly clear: βˆ’K-K must equal βˆ’9-9, which means K=9K=9. And K must equal 9 for the constant term as well. Bingo! Both parts of the equation agree. This is the definitive proof that the transformation from r(x) to g(x) is a vertical stretch by a factor of 9. When you multiply the entire function (meaning all of its y-values) by a constant K, you are performing a vertical stretch if |K| > 1 or a vertical compression if 0 < |K| < 1. In our case, since K=9, we have a clear and powerful vertical stretch. It's like taking a rubber band and pulling it upwards, making every point on the graph climb nine times higher (or drop nine times lower, if it's already negative) from the x-axis. This transformation affects the entire output of the function proportionally, leading to a much steeper and visually