Sunday, May 20, 2018

Question. Use Bessel’s Interpolation formula find y25? given y20=24, y24=32, y28=35 and y32=40

Question. Use Bessel’s Interpolation formula find y25?  

given y20=24, y24=32, y28=35 and y32=40 

Sol:


  u       x       y         f(x)        2f(x)        3f( x)
-1      20     24
                                  8
 0      24     32                          -5
                                  3                                 7
 1     28      35                           2
                                  5
2      32      40


     x = a + uh


25  = 24 + u(4)


   u = 25 – 24
             4


 [u = 0.25]


f(u) = { 32 + 35 + (0.25 – ½ ) 3
                 2                                2
      
+ 0.25(0.25 – 1) { -5 + 2 }
       2 × 1                 2


+  0.25(0.25 – 1)(0.25 – ½ ) (7)
                2× 1


= 33.5 – 0.75 + 0.25(-0.75) (-3)
                              2           2

     
+ 0.25(-0.75) (-0.25)(7)
                 6


= 33.5 – 0.75 + 0.140625 + 0.05468


= 32.9453

Saturday, May 19, 2018

Bessel's Interpolation Formula

Formula:


f(u) = { f(0) + f(1) + ( u – 1 ) f(0)
                  2                          2

    +   u(u – 1) { 2 f(-1) + ∆2 f(0) }
                2i                         2

+  u(u – 1) (u – ½)3 f(-1)
             3i

+ u(u + 1)(u – 1)(u – 2) { 4f(-2) + ∆4f(-1) }
                 4i                               2

 +. . . . . . .  .   . .. .. .. . . . .. . . . . .

Friday, May 18, 2018

Laplace – Everett’s Formula

Formula:
F(u) = {  u  f( 1) + u(u – 1)(u + 1) 2 f(0)
             1i                   3i

    + u(u – 1)(u + 1)(u – 2)(u + 2)4f(-1)}
                             5i

   +{ w  f(0) + w(w – 1)(w + 1)2f(-1)
       1i                     3i

   + w(w – 1)(w + 1)(w – 2)(w + 2)4f(-2)}
                           5i
+………………………..

Thursday, May 17, 2018

Using gauss backward difference formula estimate the no. of person. Wages(Ro.) belwo40 40-60 60-80 80-100 100-120 No. of person 250 120 100 70 50

Using gauss backward difference formula estimate the no. of person.
Wages(Ro.)    belwo40  40-60 60-80  80-100   100-120
No. of person  250         120    100      70             50

Sol:


u       x        f(x)        f(x)       2f(x)       3f(x)    4f(x)
-2    40      250
                                -130
-1   60       120                         110
                                  -20                          -120
0     80      100                          -10                          140
                                 -30                               20
1   100        70                           10
                                 -20
2   120        50


x = a + uh

70  = 80 + u (20)


u = 70 – 80
           20

[ u = -0.5]

f(u) = 100 + (-5)(-30) + (-0.5)(-0.5 – 1)   (-10)
                                                  2

         + (-0.5)(-0.5 – 1)(-0.5 + 1) (20)
                         6

      + (-0.5)(-0.5 – 1)(-0.5 + 1)(-0.5 – 2)  (140)
                         24

= 100 + 15 + (-3.75) + 1.25 + (-5.46875)

=  107.03 

Wednesday, May 16, 2018

Gauss Backward Difference formula


Formula:

F(u) = f(0) + u  ∆f(0) + u(u – 1)2 f(-1)
                  1i                   2i

           + u(u – 1)(u + 1)3 f(-1)
                       3i

          + u(u – 1)(u + 1)(u – 2)4 f(-2)
                         4i


Tuesday, May 15, 2018

Using gauss backward difference formula estimate the no. of person Wagrs(Ro.) below40 40-60 60-80 80-100 100-120 No. of peoples 250 120 100 70 50 (in thousands)


Sol:

  u     x     f(x)    f(x)  2f(x)   3f(x)    4f(x)

-2    40     250
                           -130
-1    60     120                110
                            -20                -120
0      80     100                -10                    140
                            -30                   20
1      100    70                  10
                            -20
2     120     50

      x = a +uh

    70 = 80 + u(20)

      u = 70 - 80 
                20

    [u = - 0.5]

f(u)= 100 + (-0.5)(-30) + (-0.5)(-0.5 - 1) (-10)
                                                2

          + (-0.5)(-0.5 - 1)(-0.5 + 1) (20)
                               6

         + (-0.5)(-0.5 - 1)(-0.5 + 1)(0.5 - 2) (140)
                                   24

     = 100 +  15 + (-3.75) + 1.25 + (-5.46875)

     =  107.03 

Monday, May 14, 2018

Gauss Backward Difference Formula


Formula:

f(u) = f(0) + u  ∆f(0) + u(u – 1)2f(-1)
                  1i                 2i

       + u(u – 1)( u + 1)3f(-1)
                     3i

       + u(u – 1)(u + 1)(u – 2)4f(-2)
                       4i

Sunday, May 13, 2018

Apply gauss’s forward formula to find the value of u9 if u0=14, u4=24, u8=32, u12= 35, u16= 40



Sol:-       x = a + uh

              9 = 8 + u(4)

             u = 9 – 8   =   1  = 0.25
                    4           4

             [u = 0.25]



u    x    f(x)   f(x)    2f(x)     3f(x)    4f(x)
-2  0    14
                     10
-1  4    24                   -2
                      8                          -3
0   8    32                    -5                          10
                      3                           7
1  12   35                     2
                      5
2  16   40


F(u) = 3.2 + 0.25 + 0.25(0.25 – 1)                           
                      1              2

+ 0.25(0.25 – 1)(0.25 + 1) (7)
              3 × 2

+ 0.25(0.25 – 1)(0.25 + 1) (0.25 – 2)  (10)
                4 × 3 × 2


f(u) = 32 + 0.75 + 0.46875 + (-0.2734375)  + 0.17089


       = 33.1162025

Saturday, May 12, 2018

Gauss forward Difference formula

Formula:

F(u) = f(0) + u  + u(u – 1) 2f(-1)
                  1i          2i

        + u(u – 1)(u + 1) 3f(-1)
                   3i

        + u(u – 1)(u + 1)(u – 2) 4 f(-2)
                          4i

       + u(u – 1)(u + 1)(u – 2)(u + 2) 5 f(-2)
                           5i
     
 + ……….. 

Friday, May 11, 2018

The population of town is as follows: x 1921 1931 1941 1951 1961 1971 Population(y) 20 24 29 36 46 51 Estimate the increase in population during the period 1955-1961



Sol:-    x = (a + nh) + uh

    1955 = 1971 + u(10)

       u = 1955 – 1971
                     10

         [u = -1.6]



x       f(x)    Ñ f(x)    Ñ2 f(x)   Ñ3f(x)   Ñ4 f(x)    Ñ5f(x)

1921  20
                      4
1931  24                      1
                     5                            1
1941   29                     2                          0
                     7                            1                     -9
1951   36                     3                         -9
                   10                           -8
1961  46                    -5      
                     5
1971   51


y(a+nh+uh) = 51 + (-1.6)(5) + (-1.6)(-1.6 + 1) (-5)
                                                       2
                    
          +(-1.6)(-1.6 + 1)(-1.6 +2) (-8)
                           3×2

          + (-1.6)(-1.6+1)(-1.6+2)(-1.6+3) ( -9)
                         4×3×2

          + (-1.6)(-1.6+1)(-1.6+2)(-1.6+3)(-1.6+4)  (-9)
                              4×3×2×1

   = 51 - 8 + (-2.4) + (-0.512) + (-0.5375) + (-0.096768)

   = 39.453732


Thursday, May 10, 2018

The population of a town as given :- Estimate the population for the year 1925. year(x) : 1891 1901 1911 1921 1931 population: 46 66 81 93 101


Sol:-
          x = (a + nh)+uh


     1925= 1931 + u(10)


          u = 1925 - 1931 
                        10

          u = -
                 10

         [u = - 0.6]

x          f(x)        Ñf(x)       Ñ2f(x)        Ñ3f(x)         Ñ4f(x)

1891     46
                           20
1901     66                            -5
                           15                                  2
1911     81                             -3                                  |-3|
                           12                                  |-1|
1921     93                            |-4|
                           |8|
1931    |101|

f(a+nh+uh) = 101 + (-0.6)(8) 

                   + (-0.6)(- 0.6+1) (-4)
                                   2

                   + (-0.6)(- 0.6+1)(- 0.6+2)(-1) 
                                            6

              + (-0.6)(- 0.6+1)(- 0.6+2)( -0.6+3)(-3)
                                           24

ð              101 – 4.8 + (-0.3)(0.4)(-4)


(-0.6)(0.4)(1.4)(-1)
                  6

+ (-0.6)(0.4)(1.4)(2.4)(-3)
                      24

ð    101 – 4.8 + 0.48 + 0.056 + 0.1008

 =  98.8368



Wednesday, May 9, 2018

Newton's Backward Difference formula

Formula:


f(a+nh+u)= f(a + n) +u   Ñf(a + nh)
                                   1!

+ u(u +1)  Ñ2f(a + nh)
        2!

+ u(u+1)(u+2)  Ñ3f(a + nh)
          3!

+u(u+1)(u+2)(u+3)  Ñ4f(a + nh)
            4!

[x = (a + nh) + uh]









Tuesday, May 8, 2018

one more question for understanding the Newton Forward D.Method


Ques:-   From the following table of year premium for policies maturing at different ages.

estimate the premium for policies maturing at the age of 46.

age:          45             50          55          60          65

premium: 114.84    96.16       83.32   74.48     68.48

Sol:-        x = a + uh

                    46 =  45 + u(5)

                     u = 46 -  45
                              5

                     |u =0.2|

x          f(x)           ∆f(x)      ∆2f(x)     ∆3f(x)    ∆4f(x)


45      114.84
                           -18.68
50      96.16                         5.84
                           -12.84                     -1.84
55      83.32                          4                            0.68
                            -8.84                       -1.16
60      74.48                        2.84
                               -6
65      68.48

f(a+uh)=114.84+0.2(-18.68) +0.2(0.2-1) (5.84)

                                                2×1

             + 0.2(0.2-1)(0.2-2)  (-1.84)
                      3×2×1

             + 0.2(0.2-1)(0.2-2)(0.2-3)   (0.68)
                     4×3×2×1

             = 114.84 - 3.736 - 0.4672 - 0.08832 -0.022848

             = 110.888032