Math Problem Statement

Consider the functions: 

f(x)=4x−1f(x)=4x−1

h(x)=4x2−1h(x)=4x2−1

g(x)=kx2g(x)=kx2 

If necessary, give answers as fractions in simplest for. For example: -3/2

(a) Find the value of hf(2)hf(2) = Answer 1 Question 1

(b) Find the value of hf(3/4)hf(3/4) = Answer 2 Question 1

(c) Find the composite function

explain ncause this is new t9o me

Solution

Let’s break down the problem step by step.

(a) Find the value of h(f(2))h(f(2))

We need to evaluate the composite function h(f(2))h(f(2)), which means we will first find f(2)f(2) and then use that result to find hh of that value.

Step 1: Find f(2)f(2)

The function for f(x)f(x) is given as: f(x)=4x1f(x) = 4x - 1 Substitute x=2x = 2 into f(x)f(x): f(2)=4(2)1=81=7f(2) = 4(2) - 1 = 8 - 1 = 7

Step 2: Use this value in h(x)h(x)

The function for h(x)h(x) is given as: h(x)=4x21h(x) = 4x^2 - 1 Now substitute f(2)=7f(2) = 7 into h(x)h(x): h(7)=4(72)1=4(49)1=1961=195h(7) = 4(7^2) - 1 = 4(49) - 1 = 196 - 1 = 195

Thus, h(f(2))=195h(f(2)) = 195.

(b) Find the value of h(f(3/4))h(f(3/4))

Again, we need to find f(3/4)f(3/4) first and then use that result to find hh.

Step 1: Find f(3/4)f(3/4)

Using the same function for f(x)f(x): f(x)=4x1f(x) = 4x - 1 Substitute x=34x = \frac{3}{4}: f(34)=4(34)1=31=2f\left(\frac{3}{4}\right) = 4\left(\frac{3}{4}\right) - 1 = 3 - 1 = 2

Step 2: Use this value in h(x)h(x)

Now substitute f(3/4)=2f(3/4) = 2 into h(x)h(x): h(2)=4(22)1=4(4)1=161=15h(2) = 4(2^2) - 1 = 4(4) - 1 = 16 - 1 = 15

Thus, h(f(3/4))=15h(f(3/4)) = 15.

(c) Find the composite function h(f(x))h(f(x))

The composite function h(f(x))h(f(x)) means we substitute f(x)f(x) into h(x)h(x). Recall that:

  • f(x)=4x1f(x) = 4x - 1
  • h(x)=4x21h(x) = 4x^2 - 1

Step 1: Substitute f(x)f(x) into h(x)h(x)

We need to replace every occurrence of xx in h(x)h(x) with f(x)f(x). This means: h(f(x))=4(f(x))21h(f(x)) = 4(f(x))^2 - 1 Substitute f(x)=4x1f(x) = 4x - 1 into this expression: h(f(x))=4(4x1)21h(f(x)) = 4(4x - 1)^2 - 1

Step 2: Expand (4x1)2(4x - 1)^2

First, expand the square: (4x1)2=(4x1)(4x1)=16x28x+1(4x - 1)^2 = (4x - 1)(4x - 1) = 16x^2 - 8x + 1

Step 3: Multiply by 4 and simplify

Now substitute this back into h(f(x))h(f(x)): h(f(x))=4(16x28x+1)1=64x232x+41h(f(x)) = 4(16x^2 - 8x + 1) - 1 = 64x^2 - 32x + 4 - 1 Simplify the constant terms: h(f(x))=64x232x+3h(f(x)) = 64x^2 - 32x + 3

Thus, the composite function h(f(x))=64x232x+3h(f(x)) = 64x^2 - 32x + 3.


Summary of Results:

  • h(f(2))=195h(f(2)) = 195
  • h(f(3/4))=15h(f(3/4)) = 15
  • h(f(x))=64x232x+3h(f(x)) = 64x^2 - 32x + 3

Would you like me to go over any part of the explanation in more detail?


Here are some related questions to expand your understanding:

  1. What happens if you switch the order and find f(h(x))f(h(x))?
  2. Can you calculate h(f(1))h(f(-1)) using the same approach?
  3. How would the result change if f(x)=2x1f(x) = 2x - 1 instead of f(x)=4x1f(x) = 4x - 1?
  4. What is the general form of h(g(x))h(g(x)) if g(x)=kx2g(x) = kx^2?
  5. What is the domain of the composite function h(f(x))h(f(x))?

Tip:

Always expand composite functions step by step, starting from the innermost function, and substitute carefully.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Composite Functions
Function Evaluation
Algebraic Manipulation

Formulas

f(x) = 4x - 1
h(x) = 4x^2 - 1
h(f(x)) = 64x^2 - 32x + 3

Theorems

Composite Function Theorem
Function Substitution

Suitable Grade Level

Grades 9-11