Math Problem Statement

Jika f(x) = 3x + 1, g(x) = 1/(x - 1), dan h(x) = x^2 - 4, tentukan (h o g o f)(x) dan (f o g o h)(x)!

Solution

The problem asks to find the compositions (hgf)(x)(h \circ g \circ f)(x) and (fgh)(x)(f \circ g \circ h)(x) given the following functions:

  1. f(x)=3x+1f(x) = 3x + 1
  2. g(x)=1x1g(x) = \frac{1}{x - 1}
  3. h(x)=x24h(x) = x^2 - 4

Finding (hgf)(x)(h \circ g \circ f)(x):

This represents applying f(x)f(x), then applying g(x)g(x), and finally applying h(x)h(x).

(hgf)(x)=h(g(f(x)))(h \circ g \circ f)(x) = h(g(f(x)))

  • First, apply f(x)f(x): f(x)=3x+1f(x) = 3x + 1
  • Now, apply g(x)g(x) to f(x)f(x): g(f(x))=g(3x+1)=1(3x+1)1=13xg(f(x)) = g(3x + 1) = \frac{1}{(3x + 1) - 1} = \frac{1}{3x}
  • Finally, apply h(x)h(x) to g(f(x))g(f(x)): h(g(f(x)))=h(13x)=(13x)24=19x24h(g(f(x))) = h\left(\frac{1}{3x}\right) = \left(\frac{1}{3x}\right)^2 - 4 = \frac{1}{9x^2} - 4

Thus, (hgf)(x)=19x24(h \circ g \circ f)(x) = \frac{1}{9x^2} - 4

Finding (fgh)(x)(f \circ g \circ h)(x):

This represents applying h(x)h(x), then applying g(x)g(x), and finally applying f(x)f(x).

(fgh)(x)=f(g(h(x)))(f \circ g \circ h)(x) = f(g(h(x)))

  • First, apply h(x)h(x): h(x)=x24h(x) = x^2 - 4
  • Now, apply g(x)g(x) to h(x)h(x): g(h(x))=g(x24)=1(x24)1=1x25g(h(x)) = g(x^2 - 4) = \frac{1}{(x^2 - 4) - 1} = \frac{1}{x^2 - 5}
  • Finally, apply f(x)f(x) to g(h(x))g(h(x)): f(g(h(x)))=f(1x25)=3(1x25)+1=3x25+1f(g(h(x))) = f\left(\frac{1}{x^2 - 5}\right) = 3\left(\frac{1}{x^2 - 5}\right) + 1 = \frac{3}{x^2 - 5} + 1

Thus, (fgh)(x)=3x25+1(f \circ g \circ h)(x) = \frac{3}{x^2 - 5} + 1

Final Answers:

  1. (hgf)(x)=19x24(h \circ g \circ f)(x) = \frac{1}{9x^2} - 4
  2. (fgh)(x)=3x25+1(f \circ g \circ h)(x) = \frac{3}{x^2 - 5} + 1

Would you like any more details or further clarifications? Here are 5 related questions for further exploration:

  1. How do you evaluate the domain of the function (hgf)(x)(h \circ g \circ f)(x)?
  2. What are the domains of g(x)g(x) and h(x)h(x) separately?
  3. How does function composition relate to real-world applications?
  4. What happens if we swap the order of compositions, like (gfh)(x)(g \circ f \circ h)(x)?
  5. Can you simplify the expressions further for specific values of xx?

Tip: When composing functions, always apply them step-by-step, starting from the innermost function.