College

In Exercises 39-46, determine whether the function is even, odd, or neither.

39. [tex]h(x) = 4x^7[/tex]

40. [tex]g(x) = -2x^6 + x^2[/tex]

41. [tex]f(x) = x^4 + 3x^2 - 2[/tex]

42. [tex]f(x) = x^5 + 3x^3 - x[/tex]

43. [tex]g(x) = x^2 + 5x + 1[/tex]

44. [tex]f(x) = -x^3 + 2x - 9[/tex]

45. [tex]f(x) = x^4 - 12x^2[/tex]

46. [tex]h(x) = x^5 + 3x^4[/tex]

Answer :

To determine whether a function is even, odd, or neither, we use the following rules:

1. A function [tex]\( f(x) \)[/tex] is even if [tex]\( f(-x) = f(x) \)[/tex] for all [tex]\( x \)[/tex] in the domain of the function.
2. A function [tex]\( f(x) \)[/tex] is odd if [tex]\( f(-x) = -f(x) \)[/tex] for all [tex]\( x \)[/tex] in the domain of the function.
3. If neither of these conditions is satisfied, then the function is neither even nor odd.

Let's analyze each function:

39. [tex]\( h(x) = 4x^7 \)[/tex]
- Check [tex]\( h(-x) = 4(-x)^7 = -4x^7 = -h(x) \)[/tex].
- Conclusion: [tex]\( h(x) \)[/tex] is odd.

40. [tex]\( g(x) = -2x^6 + x^2 \)[/tex]
- Check [tex]\( g(-x) = -2(-x)^6 + (-x)^2 = -2x^6 + x^2 = g(x) \)[/tex].
- Conclusion: [tex]\( g(x) \)[/tex] is even.

41. [tex]\( f(x) = x^4 + 3x^2 - 2 \)[/tex]
- Check [tex]\( f(-x) = (-x)^4 + 3(-x)^2 - 2 = x^4 + 3x^2 - 2 = f(x) \)[/tex].
- Conclusion: [tex]\( f(x) \)[/tex] is even.

42. [tex]\( f(x) = x^5 + 3x^3 - x \)[/tex]
- Check [tex]\( f(-x) = (-x)^5 + 3(-x)^3 - (-x) = -x^5 - 3x^3 + x = -f(x) \)[/tex].
- Conclusion: [tex]\( f(x) \)[/tex] is odd.

43. [tex]\( g(x) = x^2 + 5x + 1 \)[/tex]
- Check [tex]\( g(-x) = (-x)^2 + 5(-x) + 1 = x^2 - 5x + 1 \)[/tex].
- This doesn't equal [tex]\( g(x) \)[/tex] nor [tex]\(-g(x)\)[/tex].
- Conclusion: [tex]\( g(x) \)[/tex] is neither even nor odd.

44. [tex]\( f(x) = -x^3 + 2x - 9 \)[/tex]
- Check [tex]\( f(-x) = -(-x)^3 + 2(-x) - 9 = x^3 - 2x - 9 \)[/tex].
- This doesn't equal [tex]\( f(x) \)[/tex] nor [tex]\(-f(x)\)[/tex].
- Conclusion: [tex]\( f(x) \)[/tex] is neither even nor odd.

45. [tex]\( f(x) = x^4 - 12x^2 \)[/tex]
- Check [tex]\( f(-x) = (-x)^4 - 12(-x)^2 = x^4 - 12x^2 = f(x) \)[/tex].
- Conclusion: [tex]\( f(x) \)[/tex] is even.

46. [tex]\( h(x) = x^5 + 3x^4 \)[/tex]
- Check [tex]\( h(-x) = (-x)^5 + 3(-x)^4 = -x^5 + 3x^4 \)[/tex].
- This doesn't equal [tex]\( h(x) \)[/tex] nor [tex]\(-h(x)\)[/tex].
- Conclusion: [tex]\( h(x) \)[/tex] is neither even nor odd.

Summary:

39. Odd
40. Even
41. Even
42. Odd
43. Neither
44. Neither
45. Even
46. Neither