Q. Find the domain of the function f(x)=2−2x−x21. (Enter your answer using interval notation.)
Identify Inner Function: Identify the inner function within the square root to determine where it is non-negative, as the square root function requires non-negative inputs for real number outputs.
Rewrite in Standard Form: Rewrite the quadratic equation in standard form and identify values of a, b, and c.
Check Discriminant: Use the discriminant formula, b2−4ac, to check if the quadratic equation has real roots, which will help in finding the intervals where the function under the square root is non-negative.
Solve for Roots: Since the discriminant is positive, solve for the roots of the equation using the quadratic formula, x=2a−b±b2−4ac.
Determine Non-Negative Intervals: Determine the intervals where the function under the square root, 2−2x−x2, is non-negative. This is between the roots because the parabola opens downwards (a=−1).
Write Domain: Write the domain of f(x) using interval notation, considering where the function under the square root is non-negative.
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