MathDB
Today's calculation of Integral 673

Source:

February 5, 2011
calculusintegrationtrigonometrycalculus computations

Problem Statement

Let f(x)=0x11+t2dt.f(x)=\int_0^ x \frac{1}{1+t^2}dt. For 1x<1-1\leq x<1, find cos{2f(1+x1x)}.\cos \left\{2f\left(\sqrt{\frac{1+x}{1-x}}\right)\right\}.
2011 Ritsumeikan University entrance exam/Science and Technology