Let $f(x)$ be continuous function satisfying $f(x) = \int_0^x e^{x-y} f'(y)\,dy - (x^2 - x + 1)e^x$. The value of $x$ for which $f(x) = 0$, is:
Step-by-Step Solution
Key Concept: Integral equations, differentiation under integral sign
Step 1: Rewrite the integral by factoring out the exponential term.
We start with the given functional equation:
$$f(x) = \int_0^x e^{x-y} f'(y)\,dy - (x^2-x+1)e^x$$
Factor out $e^x$ from the integral:
$$f(x) = e^x \int_0^x e^{-y} f'(y)\,dy - (x^2-x+1)e^x$$
Step 2: Introduce a substitution to simplify the expression.
Let us define:
$$g(x) = \int_0^x e^{-y} f'(y)\,dy$$
Then we can rewrite $f(x)$ as:
$$f(x) = e^x g(x) - (x^2-x+1)e^x = e^x\left[g(x) - (x^2-x+1)\right]$$
Step 3: Differentiate both sides with respect to $x$.
Using the product rule on $f(x) = e^x[g(x) - (x^2-x+1)]$:
$$f'(x) = e^x\left[g(x) - (x^2-x+1)\right] + e^x\left[g'(x) - (2x-1)\right]$$
Step 4: Use the relationship between $g'(x)$ and $f'(x)$.
From the definition of $g(x)$, we have:
$$g'(x) = e^{-x}f'(x)$$
Substituting this into the differentiated equation:
$$f'(x) = e^x\left[g(x) - (x^2-x+1)\right] + e^x\left[e^{-x}f'(x) - (2x-1)\right]$$
$$f'(x) = e^x\left[g(x) - (x^2-x+1)\right] + f'(x) - (2x-1)e^x$$
Step 5: Simplify to find an explicit form for $f(x)$.
Notice that $e^x[g(x) - (x^2-x+1)] = f(x)$ from Step 2. Substituting:
$$f'(x) = f(x) + f'(x) - (2x-1)e^x$$
The $f'(x)$ terms cancel:
$$0 = f(x) - (2x-1)e^x$$
Therefore:
$$f(x) = (2x-1)e^x$$
Step 6: Solve for $x$ when $f(x) = 0$.
Setting $f(x) = 0$:
$$(2x-1)e^x = 0$$
Since $e^x > 0$ for all real $x$, we must have:
$$2x - 1 = 0$$
$$x = \frac{1}{2}$$
**Final Answer:** The value of $x$ for which $f(x) = 0$ is $\boxed{\frac{1}{2}}$, which corresponds to **Option 1**.
Correct Answer: 2