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Question

Mathematics Question on integral

Integrate the function: 4x+12x2+x3\frac {4x+1}{\sqrt {2x^2+x-3}}

Answer

Let 4x + 1 = A ddx\frac {d}{dx}(2x2+x-3) + B
⇒ 4x+1 = A(4x+1) + B
⇒ 4x+1 = 4Ax + A + B
Equating the coefficients of x and constant term on both sides, we obtain
4A = 4 ⇒ 1
A+B = 1 ⇒ B = 0
Let 2x2 + x - 3 = t
∴ (4x+1) dx = dt
4x+12x2+x3 dx∫\frac {4x+1}{\sqrt {2x^2+x-3}}\ dx = 1tdt∫\frac {1}{\sqrt t} dt
= 2t+C2\sqrt t+C
= 22x2+x3+C2\sqrt 2x^2+x-3+C