Find the Domain and Range f(x)=x^4-8x^3+17x^2-8x+16
Problem
Solution
Identify the type of function. Since
ƒ(x) is a polynomial, it is defined for all real numbers.Determine the domain. For any polynomial, the domain is
(−∞,∞) Factor the expression to find the global minimum. Notice that the expression can be rewritten as a square of a quadratic:
ƒ(x)=(x2−4*x+4)2 Simplify the quadratic inside the square. Since
x2−4*x+4=(x−2)2 the function becomesƒ(x)=((x−2)2)2=(x−2)4 Analyze the range. The expression
(x−2)4 is always non-negative because it is raised to an even power.Find the minimum value. The minimum occurs when
x−2=0 which givesƒ(2)=0 Since the leading coefficient is positive and the degree is even, the function goes to∞ asx goes to±∞
Final Answer
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