Given: \(f(x)=x^3+3x-9\) on \([-2,3]\). Since \(f'(x)=3x^2+3>0\), \(f\) is increasing, so the greatest value is at \(x=3\): \(f(3)=27\).
Sum to infinity of decreasing GP: \(S=\dfrac{a}{1-r}=27\) with \(0
Also \(f'(0)=3\Rightarrow\) difference of first two terms: \(a-ar=a(1-r)=3\).
From \(a=\;27(1-r)\), plug into \(a(1-r)=3\): \(27(1-r)^2=3\Rightarrow(1-r)^2=\dfrac{1}{9}\Rightarrow 1-r=\dfrac{1}{3}\) (take positive)
Common ratio: \(r=1-\dfrac{1}{3}=\boxed{\dfrac{2}{3}}\).
Not Available
\[ x = 1 + 2^{1/6} + 4^{1/6} + 8^{1/6} + 16^{1/6} + 32^{1/6} \]
\[ x = 1 + a + a^2 + a^3 + a^4 + a^5 = 1 + \frac{a(a^5 - 1)}{a - 1} \]
\[ x = 1 + \frac{2 - a}{a - 1} = \frac{1}{a - 1} \Rightarrow 1 + \frac{1}{x} = a \Rightarrow \left(1 + \frac{1}{x} \right)^{24} = a^{24} \]
\[ a = 2^{1/6} \Rightarrow a^{24} = (2^{1/6})^{24} = 2^4 = \boxed{16} \]
✅ Final Answer: $\boxed{16}$
The exponent is an infinite geometric series: $$ 1 + |\sin x| + |\sin x|^2 + |\sin x|^3 + \cdots $$
This is a geometric series with first term \( a = 1 \), common ratio \( r = |\sin x| \in [0,1] \), so: $$ \text{Sum} = \frac{1}{1 - |\sin x|} $$
$$ 5^{\frac{1}{1 - |\sin x|}} = 25 = 5^2 $$
Equating exponents: $$ \frac{1}{1 - |\sin x|} = 2 \Rightarrow 1 - |\sin x| = \frac{1}{2} \Rightarrow |\sin x| = \frac{1}{2} $$
We want all \( x \in (-\pi, \pi) \) such that \( |\sin x| = \frac{1}{2} \)
So \( \sin x = \pm \frac{1}{2} \). Within \( (-\pi, \pi) \), the values of \( x \) satisfying this are:
✅ Final Answer: $\boxed{4}$ solutions
If one Arithmetic Mean (AM) \( a \) and two Geometric Means \( p \) and \( q \) are inserted between any two positive numbers, find the value of: \[ p^3 + q^3 \]
\[
pq = \sqrt[3]{A^2B} \cdot \sqrt[3]{AB^2} = \sqrt[3]{A^3B^3} = AB
\]
\[
p^3 = A^2B, \quad q^3 = AB^2
\]
\[
p^3 + q^3 = A^2B + AB^2 = AB(A + B)
\]
\[ 2apq = 2 \cdot \frac{A + B}{2} \cdot AB = AB(A + B) \]
\( \boxed{p^3 + q^3 = 2apq} \)
Given: The sequence is in H.P. with \(a_m = n\) and \(a_n = m\) \((m \ne n)\).
In an H.P., reciprocals of terms form an A.P. So, \(\tfrac{1}{a_m} = \tfrac{1}{n}\) and \(\tfrac{1}{a_n} = \tfrac{1}{m}\).
This A.P. leads to common difference \(d = \tfrac{1}{mn}\) and first term \(A = \tfrac{1}{mn}\).
Thus, the reciprocal of the \((m+n)\)th term is:
\(b_{m+n} = \tfrac{m+n}{mn}\)
Hence, the \((m+n)\)th term of H.P. is:
\(a_{m+n} = \dfrac{mn}{m+n}\)
Solution:
Even numbers from 100 to 998: count $= \frac{998-100}{2}+1=450$.
Exclude evens divisible by $3$ or $5$ using inclusion–exclusion:
Forbidden $=150+90-30=210$ ⇒ Allowed $=450-210={240}$.
Given: \( f(x) = x^3 + 3x - 9 \)
The sum of infinite GP = max value of \( f(x) \) on [−2, 3]
The difference between first two terms = \( f'(0) \)
Step 1: \( f(x) \) is increasing ⇒ Max at \( x = 3 \)
\( f(3) = 27 \Rightarrow \frac{a}{1 - r} = 27 \)
Step 2: \( f'(x) = 3x^2 + 3 \Rightarrow f'(0) = 3 \)
⇒ \( a(1 - r) = 3 \)
Step 3: Solve:
\( a = 27(1 - r) \)
\( \Rightarrow 27(1 - r)^2 = 3 \Rightarrow (1 - r)^2 = \frac{1}{9} \Rightarrow r = \frac{2}{3} \)
✅ Final Answer: \( r = \frac{2}{3} \)
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and More.