Evaluate the following integrals –

Let


Let us assume




We know and derivative of a constant is 0.


3x + 1 = λ(0 – 3 – 2×2x2-1) + μ


3x + 1 = λ(–3 – 4x) + μ


3x + 1 = –4λx + μ – 3λ


Comparing the coefficient of x on both sides, we get


–4λ = 3


Comparing the constant on both sides, we get


μ – 3λ = 1





Hence, we have


Substituting this value in I, we can write the integral as






Let


Now, put 4 – 3x – 2x2 = t


(–3 – 4x)dx = dt (Differentiating both sides)


Substituting this value in I1, we can write




Recall







Let


We can write 4 – 3x – 2x2 = –(2x2 + 3x – 4)








Hence, we can write I2 as




Recall






Substituting I1 and I2 in I, we get



Thus,


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