NIMCET 2013 — Mathematics PYQ
NIMCET | Mathematics | 2013The value of 931⋅991⋅9271…∞ is:
Choose the correct answer:
- A.
3
(Correct Answer) - B.
6
- C.
9
- D.
None of these
3
Explanation
Solution
1. Use the Property of Exponents:
Since the bases are the same, the powers are added:
2. Identify the Infinite Geometric Progression (G.P.) in the Power:
Let S=31+91+271+…∞
-
First term (a)=31
-
Common ratio (r)=1/31/9=31
3. Calculate the Sum of the Infinite G.P. (S∞):
Using the formula S∞=1−ra (where |r| < 1):
4. Substitute the Sum back into the Power:
Explanation
Solution
1. Use the Property of Exponents:
Since the bases are the same, the powers are added:
2. Identify the Infinite Geometric Progression (G.P.) in the Power:
Let S=31+91+271+…∞
-
First term (a)=31
-
Common ratio (r)=1/31/9=31
3. Calculate the Sum of the Infinite G.P. (S∞):
Using the formula S∞=1−ra (where |r| < 1):
4. Substitute the Sum back into the Power:
