f(x) and g(x) are 2 polynomial functions such that f(g(x)) = x2 + 12x ...
Given:
- f(x) and g(x) are two polynomial functions.
- f(g(x)) = x^2 + 12x + 33
- g(f(x)) = x^2 - 4x + 5
- f(26) = 46
To find:
The maximum possible value of f(3)
Explanation:
We are given two composite functions f(g(x)) and g(f(x)) and their respective expressions. We need to find the maximum possible value of f(3), given that f(26) = 46.
Step 1: Finding g(x)
To find g(x), we can equate g(f(x)) to the given expression x^2 - 4x + 5:
g(f(x)) = x^2 - 4x + 5
Comparing this with the given expression g(f(x)) = x^2 - 4x + 5, we can conclude that f(x) = x^2 - 4x + 5.
Step 2: Finding g(x)
Now that we have the expression for f(x), we can substitute it into f(g(x)):
f(g(x)) = x^2 + 12x + 33
Substituting g(x) = x^2 - 4x + 5 into f(g(x)), we get:
f(x^2 - 4x + 5) = x^2 + 12x + 33
Let's simplify this equation to find f(x).
Step 3: Simplifying the equation
Expanding the function f(x^2 - 4x + 5), we get:
f(x^2 - 4x + 5) = (x^2 - 4x + 5)^2 - 4(x^2 - 4x + 5) + 5
Expanding further:
f(x^2 - 4x + 5) = x^4 - 8x^3 + 29x^2 - 76x + 45
Comparing this expression with f(g(x)) = x^2 + 12x + 33, we can conclude that:
f(x) = x^4 - 8x^3 + 29x^2 - 76x + 45
Step 4: Finding f(3)
To find f(3), we substitute x = 3 into the expression for f(x):
f(3) = 3^4 - 8(3)^3 + 29(3)^2 - 76(3) + 45
= 81 - 216 + 261 - 228 + 45
= -57
Therefore, the maximum possible value of f(3) is -57.
f(x) and g(x) are 2 polynomial functions such that f(g(x)) = x2 + 12x ...
We know that f(g(x)) =x2 + 12x +33
Thus f(g(f(x))) = f(x2) + 12f(x) + 33
Putting g(f(x)) = x2 + 4x + 5
Thus f(x2 + 4x + 5) = f(x)2 + 12f(x) + 33
Given f(26) = 46
putting x2 + 4x + 5 = 26
Or x2 + 4x - 21 = 0
Or (x+7)(x-3) =0.
Putting x = 3 in f(x2 + 4x + 5) = f(x)2 + 12f(x) + 33
f(26) = 46 = f(3)2+12f(3)+33
Or f(3)2 + 12f(3) - 13 = 0
(f(3)+13)(f(3)-1) = 0 Thus f(3) = 1 or -13
1 > -13 so it is the answer