JEE Main2003MathematicsPermutation and CombinationActual
If ^n C_r denotes the number of combination of n things taken r at a time, then the expression ^n C_ r+1 + ^n C_ r-1 +2 x^n C_r equals
Options
- An+1 r+1
- B^ n+2 C_r
- Cn+2 r+1
- D^ n+1 C_r
Correct answer
C. n+2 r+1
Step-by-step solution
After t; velocity = f t V_ B A = f t+(- u )= f^2 t^2+u^2-2 f u t For max. and min. d dt ( V _ BA ^2 )=2 f ^2 t -2 fu =0 or t = u f Therefore, total no. of values of r =33 .