Calculate the arc length of y=ln(cos(x))y = \ln(\cos(x))y=ln(cos(x)) for 0≤x≤π40 \le x \le \frac{\pi}{4}0≤x≤4π.
ln(2+1)\ln(\sqrt{2}+1)ln(2+1)
ln(2−1)\ln(\sqrt{2}-1)ln(2−1)
2\sqrt{2}2
π4\frac{\pi}{4}4π