Problem

Consider the function f(x)=3x2+12x3
a. Determine, without graphing, whether the function has a minimum value or a maximum value.
b. Find the minimum or maximum value and determine where it occurs.
c. Identify the function's domain and its range.
a. The function has a value.

Answer

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Answer

Final Answer: The function f(x)=3x2+12x3 has a maximum value of 9 at x=2. The domain of the function is all real numbers and the range is y9.

Steps

Step 1 :The function given is f(x)=3x2+12x3.

Step 2 :Since the coefficient of x2 is negative, the function opens downwards. Therefore, the function has a maximum value.

Step 3 :The maximum value of a quadratic function f(x)=ax2+bx+c occurs at x=b2a.

Step 4 :Substituting a=3 and b=12 into the formula, we get x=122(3)=2.

Step 5 :The maximum value of the function is f(2)=3(2)2+12(2)3=9.

Step 6 :The domain of the function is all real numbers, because any real number can be substituted for x in the function.

Step 7 :The range of the function is y9, because the maximum value of the function is 9 and the function opens downwards.

Step 8 :Final Answer: The function f(x)=3x2+12x3 has a maximum value of 9 at x=2. The domain of the function is all real numbers and the range is y9.

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