1 13. Evaluate dx . (5 points) V2x -1 2 -x +C O + C O V2x - 1+C None of these 14. Evaluate dx . (5 points) V1-2x O -V1-2x + C O Lnv1-2x + C O V1-2x + C O 1 + C VX-X 215. Evaluate x2 (x3 +1) dx . (5 points) O - + X + C 4 O (x3 + 1)" + C 12 O x3 +1) + C 4 None of these x/4 16. Use your calculator to evaluate [ xtan(x) dx . (5 points) o 0.1858 2.435 0.20017. Use your calculator to evaluate [ xsin(x) dx . (5 points) 0.152 O -0.218 0.262 O -0.555 x/4 18. Use your calculator to evaluate [ xcos(x) dx . (5 points) 0.152 0.218 O 0.262 0.555