Calculate the area under the graph of f(x)=1/(x^2+1) in the first quadrant

a) pi/4
b) pi/2
c) pi
d) infinite

3 answers

c'mon - this is one of the standard forms -- arctan(x)
I don't understand. what do you mean?
a trig substitution is used when calculating the integral

as oobleck says, it's a standard trick