
Last updated at Nov. 28, 2017 by Teachoo
Transcript
Example 13 Find r, if 5 4Pr = 6 4Pr-1 Now it is given that 5 4Pr = 6 5Pr-1 5 Γ 4!/(4 β π)! = 6 Γ 5!/(5β (π β 1))! 5 Γ 4!/(4 β π)! = 6 Γ 5!/(5 β π + 1)! 5 Γ 4!/(4 β π)! = 6 Γ 5!/(6 β π)! (6 β π)!/(4 β π)! = (6 Γ 5!)/(5 Γ 4! ) ((6 β π)(5 β π)(4 β π)!)/(4 β π)! = (6 Γ 5!)/(5 Γ 4! ) (6 β r) (5 β r) = (6 Γ 5!)/(5 Γ 4! ) (6 β r) (5 β r) = (6 Γ 5 Γ 4!)/(5 Γ 4! ) (6 β r)(5 β r) = 6 6(5 β r) β r(5 β r) = 6 30 β 6r β 5r + r2 = 6 30 β 11r + r2 = 6 r2 β 11r + 30 = 6 r2 β 11r + 30 β 6 = 0 r2 β 11r + 24 = 0 r β 8r β 3r + 24 = 0 r(r - 8) β 3(r β 8) = 0 (r β 8) (r β 3) = 0 Hence r = 3, 8.
Ex 7.1,4 Important
Example 13 Important You are here
Example 16 Important
Ex 7.3,3 Important
Ex 7.3,6 Important
Ex 7.3,10 Important
Example 19 Important
Ex 7.4, 6 Important
Ex 7.4, 8 Important
Example 23 Important
Misc 3 Important
Misc 4 Important
misc 7 Important
Misc 10 Important
Misc 11 Important
About the Author