यदि `2P(5,3) = P(n,4)` तो n का मान ज्ञात कीजिए ।

Explanation

प्रश्नानुसार `2P(5,3) =P(n,4)`
`rArr P(n,4) = 2P(5,3)`
`rArr (n!)/((n-4)!) = (2.5!)/((5-3)!) = (2.5!)/(2!)`
`rArr n(n-1) (n-2) (n-3) = 5!`
`rArr n(n-1)(n-2)(n-3) = 5.4.3.2.1`
`rArr n(n-1) (n-2)(n-3) = 5(5-1)(5-2)(5-3)`
`rArr n = 5`