Let the quadratic function y f x satisfy f 0 1, and f x 1 f x 1 4x, find the analytic formula of f

Updated on educate 2024-03-05
18 answers
  1. Anonymous users2024-02-06

    Solution: Let the analytic formula of the quadratic function be f(x)=ax 2+bx+cf(0)=1

    So c=1 f(x)=ax 2+bx+1

    f(x+1)-f(x-1)=4x

    f(1+1)-f(1-1)=4

    f(2)=5

    f(-1+1)-f(-1-1)=-4

    f(-2)=5

    4a+2b+1=5

    4a-2b+1=5

    b=0a=5/4

    f(x)=x^2+1

  2. Anonymous users2024-02-05

    Let f(x)=ax 2+bx+c, because f(0)=1, then c=1f(x+1)=a(x+1) 2+b(x+1)+1a(x 2+2x+1)+bx+b+1

    ax^2+(2a+b)x+a+b+1

    f(x-1)=a(x-1)^2+b(x-1)+1a(x^2-2x+1)+bx-b+1

    ax^2+(b-2a)x+a-b+1

    So f(x+1)-f(x-1)=4ax+2b, and because f(x+1)-f(x-1)=4x

    So a=1, b=0

    So f(x)=x 2+1

  3. Anonymous users2024-02-04

    Let f(x)=ax 2+bx+c be brought in and it will be found.

  4. Anonymous users2024-02-03

    Let f(x)=ax 2+bx+c be observed when f(0)=1, and the solution is c=1

    From f(x+1)-f(x)=4x to obtain a(x+1) 2+b(x+1)-ax 2-bx=4x, (2a-4)x+(a+b)=0, for any x is destroyed, 2a-4=0, a+b=0

    Solve the defeat macro sum to get a=2, b=-2

    f(x)=2x^2-2+1.

  5. Anonymous users2024-02-02

    Solution: Let the quadratic function f(x) ax 2 bx c,a≠0;

    then f(x+1) a(x+1) 2 b(x+1) c;

    From f(0)3, we get c3

    f(x+1)-f(x)=4x

    A (Ax Judgment x +1) 2 B (Punch x + 1) C-(ax 2 bx C) 4x, 2ax a b 4x, then 2A 4, A 2, Silver not a b 0, b -2

    Quadratic function f(x) 2x 2-2x+3

  6. Anonymous users2024-02-01

    Let f(x)=ax 2+bx+c

    Because f(0)=1, c=1

    Because: f(x+1)-f(x)=2x+1, f(x+1)=f(x)+2x+1

    When x=0, so f(1)=f(0)+1=1+1=2, when x=1, f(2)=f(1)+2+1=5, we get: a+b+1=2,4a+2b+1=5

    So a=1, b=0

    f(x)=x^2 +1

  7. Anonymous users2024-01-31

    y=f(x) is a 2th order function.

    Let f(x)=ax 2+bx+c

    f(0)=1==>c=1

    f(x+1)-f(x)=2x

    then there is a(x+1) 2+b(x+1)+1-ax 2-bx-1=2x2ax+a+b=2x

    Equation identity. Then there is 2a=2 ,a+b=0 ==>a=1,b=-1, so f(x)=x 2-x+1

    Note: Because in x different cases.

    There is f(x+1)-f(x)=2x

    After simplification, there is 2ax+a+b=2x

    To make 2ax+a+b=2x true.

    Only when 2a=2, a+b=0, 2ax+a+b=2x is true, x is any value, that is, the solution is 2a=2, a+b=0, and we get a=1, b=-1

  8. Anonymous users2024-01-30

    Let f(x)=ax 2+bx+c

    f(0)=0 is substituted into f(x)=ax 2+bx+c according to f(x+1)-f(x)=2x=2x, respectively.

    3 equations are obtained: 4a+2b+c=3

    0+0+c=1

    a+b+c=1 just solve it and get a=1 b=-1 c=1.

    f(x)=x 2-x+1 Try to keep it simple, not that complicated.

  9. Anonymous users2024-01-29

    Bring x=-1 into f(x+1)=f(x)+x+1 Solve f(-1)=0 Bring x=0 into f(x+1)=f(x)+x+1 to solve f(1)=1 Then there are 3 points (0,0) (1,0) (1,1) Then let the analytic formula and bring in to solve the solution: a=1 2 b=1 2 c=0 f(x)=1 2x +1 2x

  10. Anonymous users2024-01-28

    Hello! We're happy to answer for you! Hello dear, this question is a bit complicated, I need to think about it a little more, you wait a minute. Thank you, dear. Questions.

    What about the answer. It is known that f(x) is a quadratic function, if f(0)=0, and f=f+x+1Find the expression for f.

    Dear, I'm not a robot, I can see the answer at a glance, I have to calculate and think about it. Wait a minute.

    Hello dear, the answer is y

    Questions. My dear.

    It was f(x) that was asked

    The solution to this problem is:

    Use the condition f=f+x+1 known to the problem.

    You can calculate the value at x 1, x = 0, x -1, and then you can find it.

    My dear, y and f mean the same thing, both are symbols that represent a function.

    f(x) means the same as what I wrote above.

    This kind of question is simple. Dear, do you want me to teach you more? 

  11. Anonymous users2024-01-27

    Since f(x) is a quadratic function, let .

    f(x)=ax^2+bx+c

    f(0)=8

    f(0)=c=8

    f(x+1)-f(x)

    a(x+1)^2+b(x+1)-(ax^2+bx)=2ax+(a+b)

    2x+1 so has: 2a=-2

    A+B=1 Combined (1)(2) launched.

    a=-1,b=2

    So f(x)=-x 2+2x+8

    f(x)=-x^2+2x+8

    (x-1)^2+9<=9

    y=log3(f(x))

    log3(9)=2

    So the range of y is (negative infinity, 2].

  12. Anonymous users2024-01-26

    Let f(x)=ax 2+bx+c(a≠0).

    f(0)=c=0

    f(x+1)=a(x+1) 2+b(x+1)=ax 2+bx+x+1 then, 2ax+a+b=x+1

    The corresponding coefficients are equal: a = 1 2, b = 1 2

    Then, f(x)=1 2 x 2 +1 2 x=1 2(x 2+x).

  13. Anonymous users2024-01-25

    Solution: 1 set.

    y=f(x)=ax²+bx+c

    then f(x+1)-f(x-1)=...=4ax+2b=4xCompare the coefficients on both sides, there is.

    4a=4, 2b=0

    Therefore a=1 b=0

    f(0)=c=1

    Therefore f(x)=x +1

    2 f(-x)=x²+1=f(x)

    Therefore, it is an even function.

    3 ymin=f(0)=1

    ymax=f(2)=5

  14. Anonymous users2024-01-24

    1.The quadratic function y=f(x) satisfies f(0)=1, let f(x)=ax 2+bx+1, f(x+1)-f(x-1)=4ax+2b=4x, and the comparison coefficients are 4a=4,2b=0,a=1,b=0.

    f(x)=x^2+1.

    2.Obviously f(-x) = f(x) and f(x) is an even function.

    f(2)=5>f(-1), and the range of f(x) on [-1,2] is [1,5].

  15. Anonymous users2024-01-23

    1 Let the quadratic function y=ax 2+bx+c c=0 because f(0)=0 so c=0

    a(x+1)^2+b(x+1)-a(x-1)^2-b(x-1)=4xa(2x+2)+2b=4x

    2ax+2(a+b)=4x

    a=2 b=-2

    So f(x)=2x2-2x

    2.f(-x)=2x 2+2x≠f(x) f(-x)=2x 2+2x≠-f(x) So the function is non-odd and non-even.

    When x=1 2, the minimum value of the function is -1 4

    The maximum value f(-1)=f(2)=17 4

  16. Anonymous users2024-01-22

    (1) Let f(x)=ax 2+bx+c, because f(0)=1, so c=1, because f(x+1)-f(x-1)=4ax+2b=4x, so a=1, b=0

    f(x)=x^2+1

    2) f(-x)=x 2+1=f(x), so f(x) is an even function (3) the range is [1,5], the minimum value = f(0)=1, and the maximum value = f(2)=5

  17. Anonymous users2024-01-21

    From f(0)=1, when x=-1, there is f(0)-f(-2)=-4 to get f(-2)=5, and similarly when x=1, there is f(2)-f(0)=4

    f(2)=5

    Let the quadratic function y=f(x)=ax 2+bx+c, and f(0)=1

    f(-2)=5

    f(2)=5 substitution, get.

    a=1, b=0, c=1, so there is.

    f(x)=x^2+1;

    f(x)=x 2+1, f(-x)=x 2+1, i.e. f(x)=f(-x).

    Apparently an even function;

    f(x)=x 2+1, we know that when x=0, there is a maximum value of 1, and f(2)=5, so the value range on [-1,2] is [1,5].

  18. Anonymous users2024-01-20

    1.Let f(x)=ax 2+bx+c, because f(0)=1, so c=1, and because f(x+1)=a(x+1) 2+b(x+1)+c, f(x-1)=a(x-1) 2+b(x-1)+c, so f(x+1)-f(x-1)=4ax+2b=4x, so a=1, b=0, c=1

    So f(x)=x 2+1

    is an even function, symmetrical with respect to the y-axis, with the opening pointing upwards. So the maximum value of f(x) is f(2)=5, the minimum value is f(0)=1, and the range is [1,5].Complete.

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