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CGP EDU Academic Team
Published on: August 13, 2026
Prove that n C r + n–1 C r + n–2 C r + .............. + r C r = n+1 C r+1
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n C r + n – 1 C r + ...... + r C r
= Co-efficient of x r in (1 + x) n + (1 + x) n –1 + ..... + (1 + x) r
= Co-efficient of x r in (1 + x) r 
= Co-efficient of x r + 1 in (1 + x) n + 1 = n + 1 C r + 1
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