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| Some particular expansions for Positive Integral Index |
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For n  N, we have: |
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a) (a - b)n  (a +(- b))n |
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| Note 1: |
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| It is advisable to remember the following values. |
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| Note 2: |
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Working rules for expanding (a + b)n, n  N |
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| Step 1: The value of index, n implies that there will be n+1 terms in the expansion of (a + b)n. |
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| Step 2: Write the first term: nC0anb0. |
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| Step 3: For the second term, take coefficient as nC1, decreases the power of 'a' by 1 and increases the power of 'b' by 1. Thus, |
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| the second term is nC1an-1b1. |
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| Step 4: For the third term, take coefficient as nC2, power of 'a' as n-2 and power of 'b' as 2. Continue this process repeatedly till the last term nCna0bn is obtained. |
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