Question #f0f34
1 Answer
Jan 30, 2018
Explanation:
#"using the definition of "^nP_r#
#•color(white)(x)^nP_r=(n!)/((n-r)!)#
#"where "n! =n(n-1)(n-2) ...... xx3xx2xx1#
#rArr^5P_5=(5!)/((5-5)!)=(5!)/(0!)#
#" note that "[0! =1]#
#rArr^5P_5=(5xx4xx3xx2xx1)/1=120#