WBJEE · Maths · Binomial Theorem
The co-efficient of \(a^{3} b^{4} c^{5}\) in the expansion of \((b c+c a+a b)^{6}\) is
- A \(\frac{12 !}{3 ! 4 ! 5 !}\)
- B \(\frac{6 !}{3 !}\)
- C 33
- D 3. \(\left(\frac{6 !}{3 ! 3 !}\right)\)
Answer & Solution
Correct Answer
(D) 3. \(\left(\frac{6 !}{3 ! 3 !}\right)\)
Step-by-step Solution
Detailed explanation
\(\left\{\frac{6 !}{p ! q ! r !} a^{q+r} b^{p+r} c^{p+q}\right.\) \(q+r=3, p+r=4, p+q=5, p+q+r=6\) \(\Rightarrow p=3, q=2, r=1\) co-efficient \(=\frac{6 !}{3 ! 2 !}\)
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