The sum of infinite terms of a decreasing GP is equal to the greatest value of the function in the interval [-2,3] and the difference between the first two terms is f'(0). Then the common ratio of GP is
If a, a, a_2, ., a_{2n-1},b are in AP, a, b_1, b_2,...b_{2n-1}, b are in GP and a, c_1, c_2,... c_{2n-1}, b are in HP, where a, b are positive, then the
equation a_n x^2-b_n+c_n has its roots
Given: Harmonic mean is 4:
\frac{2ab}{a + b} = 4 \quad \text{(1)}
Arithmetic mean A = \frac{a + b}{2} ,
Geometric mean G = \sqrt{ab}
Given:
2A + G^2 = 272 \cdot \frac{a + b}{2} + ab = 27 \Rightarrow a + b + ab = 27 \quad \text{(2)}
From (1): Multiply both sides by a + b :
2ab = 4(a + b) \Rightarrow ab = 2(a + b) \quad \text{(3)}
Substitute (3) into (2):
a + b + 2(a + b) = 27 \Rightarrow 3(a + b) = 27 \Rightarrow a + b = 9
Then from (3):
ab = 2 \cdot 9 = 18
Now solve:
x^2 - (a + b)x + ab = 0 \Rightarrow x^2 - 9x + 18 = 0\Rightarrow x = 3, 6 Final Answer: \boxed{3 \text{ and } 6}
Three positive number whose sum is 21 are in arithmetic progression. If 2, 2, 14 are added to them respectively then resulting numbers are in geometric progression. Then which of the following is not among the three numbers?
The value of the sum \frac{1}{2\sqrt{1}+1\sqrt{2}}+\frac{1}{3\sqrt{2}+2\sqrt{3}}+\frac{1}{4\sqrt{3}+3\sqrt{4}}+...+\frac{1}{25\sqrt{24}+24\sqrt{25}} is
An arithmetic progression has 3 as its first term.
Also, the sum of the first 8 terms is twice the sum of
the first 5 terms. Then what is the common
difference?
The sum of infinite terms of decreasing GP is equal to the greatest value of the function f(x) = x^3
+ 3x – 9 in the
interval [–2, 3] and difference between the first two terms is f '(0). Then the common ratio of the GP is