Question:
If the third term in the binomial expansion of \(\left(1+x^{\log_2x}\right)^5\) equals 2560, then a possible value of \(x\) is -
If the third term in the binomial expansion of \(\left(1+x^{\log_2x}\right)^5\) equals 2560, then a possible value of \(x\) is -
Show Hint
The third term is \(T_3=\binom52\left(x^{\log_2x}\right)^2\); take \(\log_2\) after equating it to 2560.
Updated On: Nov 5, 2026
- \(2\sqrt2\)
- \(4\sqrt2\)
- \(\frac18\)
- \(\frac14\)
Show Solution
Verified By Collegedunia
The Correct Option is D
Solution and Explanation
\(T_3=\binom52\left(x^{\log_2x}\right)^2=10\,x^{2\log_2x}=2560\Rightarrow x^{2\log_2x}=256\).
Take \(\log_2\): \(2(\log_2x)^2=8\Rightarrow(\log_2x)^2=4\Rightarrow\log_2x=\pm2\).
So \(x=4\) or \(x=\frac14\). Among the options only \(\frac14\) is present.
Answer: (4) \(\frac14\)
Take \(\log_2\): \(2(\log_2x)^2=8\Rightarrow(\log_2x)^2=4\Rightarrow\log_2x=\pm2\).
So \(x=4\) or \(x=\frac14\). Among the options only \(\frac14\) is present.
Answer: (4) \(\frac14\)
Was this answer helpful?
0
0
Top JEE Main Mathematics Questions
- The value of is
- The number of terms of an is even. The sum of the odd terms is and of the even terms is . The last term exceeds the first by . Then the number of terms in the series is ______.
- If , then the general value of is:
- The general solution of
- If the constant term in the binomial expansion of $\left(\frac{x^{\frac{3}{2}}}{2}-\frac{4}{x^l}\right)^9$ is $-84$ and the coefficient of $x^{-3 l}$ is $2^\alpha \beta$, where $\beta<0$ is an odd number, then $|\alpha l-\beta|$ is equal to_____
View More Questions
Top JEE Main binomial expansion formula Questions
- Number of integral terms in the expansion of \( \left( \sqrt{7} z + \frac{1}{6 \sqrt{z}} \right)^{824} \) is equal to ______.
- Coefficient of x2012 in (1-x)2008(1+x+x²)2007 is equal to ___
- In the expansion of \((1 + x)(1 - x^2) (1 + \frac 3x + \frac {3}{x^2}+ \frac {1}{x^3})^5\) the sum of coefficients of \(x^3\) and \(x^{-13}\) is
- Let \( \alpha, \beta, \gamma \) and \( \delta \) be the coefficients of \( x^7, x^5, x^3, x \) respectively in the expansion of \( (x + \sqrt{x^3 - 1})^5 + (x - \sqrt{x^3 - 1})^5, \, x > 1 \). If \( \alpha u + \beta v = 18 \), \( \gamma u + \delta v = 20 \), then \( u + v \) equals:
- For some \( n \neq 10 \), let the coefficients of the 5th, 6th, and 7th terms in the binomial expansion of \( (1 + x)^{n+4} \) be in A.P. Then the largest coefficient in the expansion of \( (1 + x)^{n+4} \) is:
View More Questions
Top JEE Main Questions
- Two masses $m$ and $\frac{m}{2}$ are connected at the two ends of a massless rigid rod of length $l$. The rod is suspended by a thin wire of torsional constant $k$ at the centre of mass of the rod-mass system(see figure). Because of torsional constant $k$, the restoring torque is $\tau =k\theta$ for angular displacement $\theta$. If the rod is rota ted by $\theta_0$ and released, the tension in it when it passes through its mean position will be:
What will be the equilibrium constant of the given reaction carried out in a \(5 \,L\) vessel and having equilibrium amounts of \(A_2\) and \(A\) as \(0.5\) mole and \(2 \times 10^{-6}\) mole respectively?
The reaction : \(A_2 \rightleftharpoons 2A\)- The value of is
- The number of terms of an is even. The sum of the odd terms is and of the even terms is . The last term exceeds the first by . Then the number of terms in the series is ______.
A black body is at a temperature of 2880 K. The energy of radiation emitted by this body with wavelength between 499 nm and 500 nm is U1, between 999 nm and 1000 nm is U2 and between 1499 nm and 1500 nm is U3. The Wien's constant, b = 2.88×106 nm-K. Then,
View More Questions