Page 309 - DMTH201_Basic Mathematics-1
P. 309

Basic Mathematics – I




                    Notes          2.  Let  y  ax  2  bx c
                                            dy
                                                  2ax b  0
                                            dx

                                             2
                                            d y
                                                 2a  0
                                            dx 2
                                                 = 2a
                                        d  3 y
                                             0
                                        dx  3
                                        d  4 y
                                             0
                                        dx  4
                                              ax b
                                   3.  Let  y
                                              cx d
                                            dy   cx d a   ax b c
                                            dx        cx d  2

                                               acx ad acx bc
                                                   cx d  2
                                                ad bc
                                                cx d  2

                                             2
                                            d y   ac bc   2c
                                            dx  2   cx d  3

                                             2
                                            d y  2c bc ad
                                            dx  2  cx d  3

                                           d 3 y  6c  2 (bc  ad )
                                           dx 3    (cx  ) d  4

                                           d  4 y  24c  3 (bc  ad )
                                           dx 4   (cx  ) d  5
                                   4.  Let y = x log x

                                            dy     1
                                                x    log x  1 log x
                                            dx    x
                                             2
                                            d y     1  1
                                                 0
                                            dx 2    x  x
                                        d 3 y  1
                                        dx  3  x  2

                                        d  4 y  2
                                        dx  4  x  3






          302                               LOVELY PROFESSIONAL UNIVERSITY
   304   305   306   307   308   309   310   311   312   313   314