(b) ] √ x ( 1 + 1 ) FOCUS ON CONCEPTS 13. Explain the connection between the chain rule for dif- ferentiation and the method of u-substitution for inte- gration. 14. Explain how the substitution u = ax + b helps to per- form an integration in which the integrand is f(ax + b), where f(x) is an easy to integrate function. 15-56 Evaluate the integrals using appropriate substitutions. .3 16. √x³ √5+ x + dx 55. 56. 57- the nee 57. 59 61 an 15. (4x-3) dx 17. sin 7x dx 18. / cos Χ cos - dx 61 19. sec 4x tan 4x dx 20. sec² 5x dx 62 21. e2x dx 22. dx 23. √1 - 4x2 25. 27. 29. [1√712² + 12 dt | 31. 6 (1-2x)³ x³ (5x4+2)³ dx dx 24. Si 26. S 28. J dx 1 + 16x2 X √4-5x2 x² +1 X √x³ + 3x sin(1/x) 30. S esin x cos x dx .3 32. 3x² x³ ex dx dx fa dx 2x 63 teg 63 dx 65 C 66 dx F