<p>If <span>\(f(x)\)</span> is a continuous function for all real values of <span>\(x\)</span> and satisfies <span>\(\int_n^{n+1} f(x) dx = 2\)</span>, <span>\(\forall n \in \mathbb{I}\)</span>, then <span>\(-\int_3^5 f(|x|) dx\)</span> is equal to</p>
<p>(a) <span>\(\frac{19}{2}\)</span></p>
<p>(b) <span>\(\frac{35}{2}\)</span></p>
<p>(c) <span>\(\frac{17}{2}\)</span></p>
<p>(d) None of these</p>
Step-by-Step Solution
Key Concept: Since f(x) has a constant integral value of 2 over every unit interval, we must decompose the integral of f(|x|) over [-5, 5] into regions where |x| changes behavior, then use the periodicity-like property that ∫_n^(n+1) f(x)dx = 2 for all integers n.
Step 1: Analyze the given integral and function properties.
The function $f(x)$ is continuous for all real values of $x$, and it satisfies the property $\int_n^{n+1} f(x) dx = 2$ for all integers $n$.
The integral to be evaluated is $-\int_3^5 f(|x|) dx$.
Step 2: Simplify the integrand using the absolute value property.
For the interval of integration $[3, 5]$, all values of $x$ are positive. Therefore, $|x| = x$ for $x \in [3, 5]$.
The integral becomes:
$$-\int_3^5 f(|x|) dx = -\int_3^5 f(x) dx$$
Step 3: Decompose the integral into unit intervals.
The interval $[3, 5]$ can be decomposed into two unit intervals starting at integers: $[3, 4]$ and $[4, 5]$.
$$-\int_3^5 f(x) dx = -\left[\int_3^4 f(x) dx + \int_4^5 f(x) dx\right]$$
Step 4: Apply the given property to each unit interval.
Using the property $\int_n^{n+1} f(x) dx = 2$:
For $n=3$: $\int_3^4 f(x) dx = 2$.
For $n=4$: $\int_4^5 f(x) dx = 2$.
Step 5: Calculate the final result.
Substitute the values back into the decomposed integral:
$$-\left[\int_3^4 f(x) dx + \int_4^5 f(x) dx\right] = -[2 + 2] = -4$$
The value of the integral is $-4$.
Note: The provided "Correct Answer: b" (which is $\frac{35}{2}$) cannot be derived from the given problem statement and conditions. The calculation above is a direct and correct evaluation of the integral as stated in the question. If the intended answer is $\frac{35}{2}$, the problem statement or the given conditions must be different. Based on the literal interpretation of the question and the provided information, the result is $-4$.
Correct Answer: b