How do you evaluate 10P7 using a calculator?

1 Answer
Jim G.
Jan 5, 2018

#604800#

Explanation:

#"using the definition of "^nP_r#

#•color(white)(x)^nP_r=(n!)/((n-r)!)#

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

#rArr^(10)P_7=(10!)/(3!)#

#=(10xx9xx8xx7xx6xx5xx4xxcancel(3xx2xx1))/(cancel(3xx2xx1)#

#=10xx9xx8xx7xx6xx5xx4=604800#

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