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Saturday, 31 October

JEE Main 2023 · MathsNumerical answerNumerical valueMediumCalculation

JEE Main 11 April 2023, Shift 1, Maths Q21

Question 21 of 90 in this shift, Maths question 21 of 30, Section B.

The mean of the coefficients of x,x2,…,x7x, x^2, \ldots, x^7 in the binomial expansion of (2+x)9(2+x)^9 is ______________.

Official answer

2736

NTA final key.

Same idea in other shifts

Asked 6× in all
  1. 27 Jan 2024, Shift 1 · Q6If A denotes the sum of all the coefficients in the expansion of (1−3x+10x2)n(1-3x+10x^2)^n and B denotes the sum of all the coefficients in the…EasySingle correct
  2. 31 Jan 2024, Shift 2 · Q23Let the coefficient of xrx^r in the expansion of (x+3)n−1+(x+3)n−2(x+2)+(x+3)n−3(x+2)2+…+(x+2)n−1(x+3)^{n-1}+(x+3)^{n-2}(x+2)+(x+3)^{n-3}(x+2)^2+\ldots+(x+2)^{n-1} be αr\alpha_r. If…HardNumerical value
  3. 13 Apr 2023, Shift 1 · Q23Let α\alpha be the constant term in the binomial expansion of (x−6x3/2)n\left(\sqrt{x}-\frac{6}{x^{3/2}}\right)^n, n≤15n\leq15. If the sum of the…HardNumerical value
  4. 28 Jul 2022, Shift 2 · Q84If 1+(2+49C1+49C2+...+49C49)(50C2+50C4+...+50C50)1+(2+{}^{49}C_1+{}^{49}C_2+...+{}^{49}C_{49})({}^{50}C_2+{}^{50}C_4+...+{}^{50}C_{50}) is equal to 2n⋅m2^n\cdot m, where m is odd, then…MediumNumerical value
  5. 2 Apr 2017 (offline) · Q67The value of (21C1−10C1)+(21C2−10C2)+(21C3−10C3)+(21C4−10C4)+…+(21C10−10C10)(^{21}C_1-{}^{10}C_1)+(^{21}C_2-{}^{10}C_2)+(^{21}C_3-{}^{10}C_3)+(^{21}C_4-{}^{10}C_4)+\ldots+(^{21}C_{10}-{}^{10}C_{10})…MediumSingle correct

Question text from the official JEE Main paper published by NTA; answer from the final answer key. Chapter, topic and idea tags, difficulty and skill are Lumi’s. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.