यदि (\frac{(n+1)!}{(n-1)!}=30) हो, तो (n) का मान क्या है?
If (\frac{(n+1)!}{(n-1)!}=30), what is the value of (n)?
Explanation opens after your attempt
Correct Answer
B. (5)
Concept
(\frac{(n+1)!}{(n-1)!}=n(n+1)), so (n(n+1)=30) gives (n=5). Reduce factorials first in such questions.
Why this answer is correct
The correct answer is B. (5). (\frac{(n+1)!}{(n-1)!}=n(n+1)), so (n(n+1)=30) gives (n=5). Reduce factorials first in such questions.
Exam Tip
(\frac{(n+1)!}{(n-1)!}=n(n+1)), इसलिए (n(n+1)=30) से (n=5)। ऐसे प्रश्नों में पहले फैक्टोरियल घटाएं।
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