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Sunday, May 19, 2013

Binomial Theorem, 4

Category: Algebra

"Published in Newark, California, USA"

Find the term which does not contain x in the expansion for


Solution:

Consider the formula in getting the value of rth term


In this problem, we need only x and y in order to solve for the value of r where x in not involve in the binomial expansion. If x is not involve in the binomial expansion, then the exponent of x is 0. Any number (except zero) raised to zero power is always equal to one.



Since we need the exponents of x in order to solve for the value of r, then we can omit y and 2 as follows








Take the logarithm on both sides of the equation to the base x, we have









Therefore, there's no x at the 3rd term.Consider again the formula in getting the value of rth term



Substitute the values of n, r, x, and y in order to get the value at the 3rd term, we have