Q79.Let f(x) be a function such that f(x + y) = f(x) ⋅f(y) for all x, y ∈N , If f(1) = 3 and ∑nk=1 f(k) = 3279 , then the value of n is (1) 6 (2) 8 (3) 7 (4) 9
What This Question Tests
This question requires recognizing that the given functional equation implies an exponential function, which forms a geometric progression, and then solving for 'n' using the sum of GP formula.
Concepts Tested
Formulas Used
f(x+y) = f(x)f(y) implies f(x) = (f(1))^x
Sum of GP: Sn = a(r^n - 1) / (r-1)
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3.17 During nuclear explosion, one of the products is 90Sr with half-life of 28.1 years. If 1mg of 90Sr was absorbed in the bones of a newly born baby instead of calcium, how much of it will remain after 10 years and 60 years if it is not lost metabolically.
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📋 Question Details
- Chapter
- Sequences & Series
- Topic
- Geometric Progression
- Year
- 2023
- Shift
- 24 Jan Shift 2
- Q Number
- Q79
- Type
- MCQ
- NCERT Ref
- Class 11 Mathematics Ch 9: Sequences and Series
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