Zaymiey

📐 Mathematics  ·  Binomial Theorem  ·  JEE

The largest term in the expansion of (3 + 5x)¹⁰ when x = 1/5 is:

Answer: T₃.

  • A T₄
  • B T₅
  • C T₃
  • D T₆

Correct answer: C. T₃

Explanation: With x=1/5, 5x=1, so T(r+1)=C(10,r)*310-r. Computing directly: T1=310=59049, T2=10*39=196830, T3=45*38=295245, T4=120*37=262440. Since T3 exceeds both T2 and T4, T3 is the largest term.

Pascal's Triangle: Binomial Coefficients11112113311464115101051n=0n=1n=2n=3n=4n=5Each entry = sum of the two entries diagonally above it (Pascal's identity); row n gives nC0...nCn

Row n of Pascal's triangle gives the coefficients nC0, nC1, ..., nCn for the expansion of (a+b)ⁿ; each number is the sum of the two numbers diagonally above it, a direct visual proof of the identity nCr = (n-1)C(r-1) + (n-1)Cr.

Concept context

Expansion of (a+b) n , general term, middle term, binomial coefficients, and greatest term

Read the full Binomial Theorem notes →