How do you find the definite integral for: (2+3x) / (4+x2) dx2+3x4+x2dx for the intervals [0, 1][0,1]?

1 Answer
Nov 23, 2017

arc tan(1/2)+3/2ln(5/4).arctan(12)+32ln(54).

Explanation:

Suppose that, I=int_0^1(2+3x)/(4+x^2)dx.I=102+3x4+x2dx.

:. I=int_0^1 2/(4+x^2)dx+int_0^1(3x)/(4+x^2)dx,

=2int_0^1 1/(2^2+x^2)dx+3/2int_0^1 (2x)/(4+x^2)dx,

=2[1/2*arc tan(x/2)]_0^1+3/2int_0^1 {d/dx(4+x^2)}/(4+x^2)dx,

=[arc tan(1/2)-arc tan(0)]+3/2[ln(4+x^2)]_0^1,

=arc tan(1/2)-0+3/2[ln(4+1^2)-ln(4+0^2)],

=arc tan(1/2)+3/2(ln5-ln4),

=arc tan(1/2)+3/2ln(5/4).