COMEDK2012MathematicsSequences and Series
If p=3^ 1 3 3^ 2 9 3^ 3 27 , then p^ 4 3 =
Options
- A3^ 1 4
- B3
- C9
- D3^ 3 4
Correct answer
B. 3
Step-by-step solution
We have, p=3^ 1 3 3^ 2 9 3^ 3 27 =3^ 1 3 [1+ 2 3 + 3 9 + . ] =3^ 1 3 [ a 1-r + a r (1-r)² ] aligned & 1 3 [ 1 1- 1 3 + 1 1 3 (1- 1 3 )² ] =& 3 aligned =3^ 1 3 [ 3 2 + 3 4 ] =3^ 1 3 [ 12+6 8 ] =3^ 1 3 ( 18 8 ) =3^ 3 4 Now, p^ 4 / 3 = (3^ 3 4 )^ 4 3 =3^ 3 4 4 3 =3¹=3