Question

How do you evaluate 10P8 using a calculator?

Answer 1

`1814400`

Explanation:

`"using the definition for " ""^nP""_r`

`"that is " ""^nP""_r=(n!)/((n-r)!)`

`"where " n! =n(n-1)(n-2)(n-3)........xx1`

`rArr""^(10)P""_8=(10!)/((10-8)!)=(10!)/(2!)larr" cancel "2!`

`=10xx9xx8xx7xx6xx5xx4xx3`

`=1814400`