Find the term independent of x in the expansion of \(\left( 2x + \frac{1}{4x^2} \right)^6\).
Solution
To find the term independent of x in the expansion of \(\left( 2x + \frac{1}{4x^2} \right)^6\), we use the binomial theorem:
\(\binom{6}{k} (2x)^{6-k} \left( \frac{1}{4x^2} \right)^k\)
The term independent of x occurs when the powers of x cancel out, i.e., when:
\((6-k) - 2k = 0\)
Solving for k gives:
\(6 - 3k = 0\)
\(k = 2\)
Substitute \(k = 2\) into the binomial term:
\(\binom{6}{2} (2x)^4 \left( \frac{1}{4x^2} \right)^2\)
\(= 15 \times 16x^4 \times \frac{1}{16x^4}\)
\(= 15\)
Thus, the term independent of x is 15.
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