Evaluate the following integral:


And also,


We know that if f(x) is an odd function,



As we know the property,



Applying this property we get,




Let x2 + x + 1 = t


(2 x + 1) dx = dt


And for limits,


At x = 0, t = 1


At x = 2, t = 7


Therefore, we get,





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