This is question 50 on page 209 from New Senior Maths : 3Unit Course.
50. By considering the coefficient of x^r in the geometric progression.
1 + (1 + x) + (1 + x)^2 + .... + (1 + x)^n
Prove that nCr + (n-1)Cr + (n-2)Cr + ... + rCr = (n+1)C(r+1)
The C acutally represent the Combination symbol. sorry, I didn't know how to use the latex equation thing.
Thanks.
50. By considering the coefficient of x^r in the geometric progression.
1 + (1 + x) + (1 + x)^2 + .... + (1 + x)^n
Prove that nCr + (n-1)Cr + (n-2)Cr + ... + rCr = (n+1)C(r+1)
The C acutally represent the Combination symbol. sorry, I didn't know how to use the latex equation thing.
Thanks.