$\"\"$ Step 1:

The sequence $\"\"$ .

The first term of sequence $\"\"$ . $\"\"$

The second term of sequence $\"\"$ .

The third term of sequence $\"\"$ .

Observe the sequence the numerator is starts with 1 and next numerators are 4, 9, 16.

Those are squares of natural numbers $\"\"$ .

The denominator is starts with 2 and next denominators are 3, 4, 5...

The denominator sequence increases with 1 unit, the nth term denominator is $\"\"$ .

The even terms are negative, so the sequence is multiplied with $\"\"$ .

The general term of the sequence is $\"\"$ .

Solution:

The general term of the sequence is $\"\"$ .