find first three terms in the expansion of ( 1 –x )^-1/4

Answer 1

Use (a+b)^n
= a^n + [n(n-1)/1!] a^(n-1) (b) + [n(n-1)(n-2)/2!] a^(n-2) b^2 + ..

(1 - x)^(-1/4)
= 1 +(-1/4) (-x) + (-1/4)(-5/4)/2 (-x)^2 + ...
= 1 + (1/4)x - (5/32)x^2 + ...

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