यदि \(U={x:x \in \mathbb{Z},-8\le x\le 8}\) और \(A={x:x \in U,x^2-2x-15\le 0}\), तो (A') में कितने सदस्य हैं?
If \(U={x:x \in \mathbb{Z},-8\le x\le 8}\) and \(A={x:x \in U,x^2-2x-15\le 0}\), how many elements are in (A')?
Explanation opens after your attempt
A. (7)
Concept
The inequality \(x^2-2x-15\le 0\) gives \(-3\le x\le 5\), so (A) has (9) integers. Since (U) has (17) elements, the complement has (17-9=8) elements.
Why this answer is correct
The correct answer is A. (7). The inequality \(x^2-2x-15\le 0\) gives \(-3\le x\le 5\), so (A) has (9) integers. Since (U) has (17) elements, the complement has (17-9=8) elements.
Exam Tip
\(x^2-2x-15\le 0\) से \(-3\le x\le 5\) मिलता है, इसलिए (A) में (9) पूर्णांक हैं। (U) में (17) सदस्य हैं, पर यहां पूरक (8) नहीं बल्कि (-8) से (-4) और (6) से (8) मिलाकर (8) होना चाहिए।
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