Show that
C₀ + C₁ + C₂ + ... + C₉ = 512
Answers
Answer:
⁹C₀ + ⁹C₁ + ⁹C₂ + ⁹C₃ + ⁹C₄ + ⁹C₅ + ⁹C₆ + ⁹C₇ + ⁹C₈ + ⁹C₉ = 512
Step-by-step explanation:
⁹C₀ + ⁹C₁ + ⁹C₂ + ⁹C₃ + ⁹C₄ + ⁹C₅ + ⁹C₆ + ⁹C₇ + ⁹C₈ + ⁹C₉ = 512
ⁿCₐ = n!/(a!(n-a)!)
LHS
= ⁹C₀ + ⁹C₁ + ⁹C₂ + ⁹C₃ + ⁹C₄ + ⁹C₅ + ⁹C₆ + ⁹C₇ + ⁹C₈ + ⁹C₉
= 9!/(0!(9-0)!) + 9!/(1!(9-1)!) + 9!/(2!(9-2)!) + 9!/(3!(9-3)!) + 9!/(4!(9-4)!) + 9!/(5!(9-5)!) + 9!/(6!(9-6)!) + 9!/(7!(9-7)!) + 9!/(8!(9-8)!) + 9!/(9!(9-9)!)
= 9!/(0!(9)!) + 9!/(1!(8)!) + 9!/(2!(7)!) + 9!/(3!(6)!) + 9!/(4!(5)!) + 9!/(5!(4)!) + 9!/(6!(3)!) + 9!/(7!(2)!) + 9!/(8!(1)!) + 9!/(9!(0)!)
= 1 + 9 + 9*8/2 + 9*8*7/(3*2) + 9*8*7*6/(4*3*2) + 9*8*7*6/(4*3*2) + 9*8*7/(3*2) + 9*8/2 + 9 + 1
= 1 + 9 + 36 + 84 + 126 + 126 + 84 + 36 + 9 + 1
= 512
= RHS
Hence
⁹C₀ + ⁹C₁ + ⁹C₂ + ⁹C₃ + ⁹C₄ + ⁹C₅ + ⁹C₆ + ⁹C₇ + ⁹C₈ + ⁹C₉ = 512
Also we can say that :
⁹C₀ + ⁹C₁ + ⁹C₂ + ⁹C₃ + ⁹C₄ + ⁹C₅ + ⁹C₆ + ⁹C₇ + ⁹C₈ + ⁹C₉is expansion of ( x + y) ⁹ where x & y = 1
= ( 1 + 1)⁹
= 2⁹
= 512