MCQ
(x - 1)4 + 4(x - 1)3 + 6(x - 1)2 + 4(x - 1) + 1 =
- Ax4
- Bx3
- Cx2
- D1
Solution:
Consider the following identity
(a + 1)4
= ((a + 1)2)2
= (a2 + 2a + 1)2
= a4 + 4a2 + 1 + 4a3 + 4a + 2a2
= a4 + 4a3 + 6a2 + 4a + 1 ...(i)
Comparing i with the given question we get
a = (x - 1)
Therefore
(x - 1)4 + 4(x - 1)3 + 6(x - 1)2 + 4(x - 1) + 1
= (x - 1 + 1)4 from (i)
= x4.
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
Given the integers r > 1, n > 2, and coefficients of (3r)th and (r + 2)nd terms in the binomial expansion of (1 + x)2n are equal, then: