# How do you evaluate 5P4?

##### 1 Answer

Jan 17, 2018

#### Explanation:

#"using the definition for "^nP_r#

#•color(white)(x)^nP_r=(n!)/((n-r)!)#

#"where "n! =n(n-1)(n-2)...... xx3xx2xx1#

#rArr^5P_4=(5!)/((5-4)!)=(5!)/(1!)#

#[1! =1]#

#rArr^5P_4=5! =5xx4xx3xx2xx1=120#