AP EAMCET2006MathematicsBasics of Mathematics
For all integers n 1 , which of the following is divisible by 9 ?
Options
- A8^n+1
- B4^n-3 n-1
- C3^ 2 n +3 n+1
- D10^n+1
Correct answer
B. 4^n-3 n-1
Step-by-step solution
4^n=(1+3)^n=1+3 n+ n(n-1) 2 ! 3^2+ 4^n-3 n-1=3^2 [ n(n-1) 2 ! + ] It is clear from above that 4^n-3 n-1 is divisible by 9 .