$\"\"$

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(a)

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The series is $\"\"$ .

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Let $\"\"$ and $\"\"$ diverges.

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$\"\"$ .

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$\"\"$

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The series diverges.

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If $\"\"$ diverges then so does $\"\"$ .

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Hence by the comparision test $\"\"$ diverges.

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If $\"\"$ and $\"\"$ diverges then the series $\"\"$ diverges too.

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The series $\"\"$ diverges. $\"\"$

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(b)

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The series is $\"\"$ .

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Let $\"\"$ and $\"\"$ diverges.

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$\"\"$ .

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$\"\"$

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The series diverges.

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If $\"\"$ diverges then so does $\"\"$ .

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Hence by the comparision test $\"\"$ diverges.

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If $\"\"$ and $\"\"$ diverges then the series $\"\"$ diverges too.

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The series $\"\"$ diverges.

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$\"\"$

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(a) The series $\"\"$ diverges.

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(b) The series $\"\"$ diverges.