need helpin solving this.

create a vector X with the elements,

http://s188.beta.photobucket.com/user/raneses88/media/exprssion_zps3b070c60.jpg.html

add up the element of the version of this vector that has 100 elements.

thanks for the help.

n= 1:100

Xn= ((-1).^n+1)/(2*n-1)

Xn =

    0.0076is this correct?

[per isakson]

Homework?

Answer 1

[Sg dg]

yup.. for me to refer against my current answers.

[Image Analyst]

You go first. You can do this in two lines of MATLAB code. What were they and what were your "current answers"? Then we can tell you if you were correct.

[Roger Stafford]

As you near the end of your one hundred terms your sum ought to be oscillating roughly equal distances on either side of pi/4. Does that help?

Answer 2

[Sg dg]

n= 1:100

n =

Columns 1 through 21

     1     2     3     4     5     6     7     8     9    10    11    12    13    14    15    16    17    18    19    20    21

Columns 22 through 42

    22    23    24    25    26    27    28    29    30    31    32    33    34    35    36    37    38    39    40    41    42

Columns 43 through 63

    43    44    45    46    47    48    49    50    51    52    53    54    55    56    57    58    59    60    61    62    63

Columns 64 through 84

    64    65    66    67    68    69    70    71    72    73    74    75    76    77    78    79    80    81    82    83    84

Columns 85 through 100

    85    86    87    88    89    90    91    92    93    94    95    96    97    98    99   100

>> Xn= ((-1).^n+1)/(2*n-1)

Xn =

    0.0076

is this correct?

[José-Luis]

No. Beware of

 * vs .*

and

 / vs ./

[Walter Roberson]

The "/" operator is for matrix division. You want ./ which is element-by-element division.

[Sg dg]

Xn= ((-1).^n+1)./(2*n-1)is this correct?

Answer 3

[Image Analyst]

Nope. n is a vector so you need ./ rather than /.

[Sg dg]

errrr.. im kinda confuse now

[Sg dg]

Xn= ((-1).^n+1)./(2*n-1)

correct?

[Walter Roberson]

You still need to add up the terms.

[Sg dg]

can u show me? i do nt understand by the terms.

[José-Luis]

 doc sum

Example:

 a = 1:10;
 sum(a)