pllllllllllllZzz ..... I need it today ;(

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mon mon
mon mon on 26 Oct 2011
*Hi evry body :)
can U help me to answer qustion num(c)? I don't Know how can i answer it :( PlZz help me =,(*
Exercise 2:
(a) Write an m-file named cosmx.m (“COS Minus X”) that defines the function:
(x) = cos x - x
Recall that a function m-file is one that starts with the word function. In this case it should start off as
function y = cosmx ( x )
% y = cosmx(x) computes the difference y=cos(x)-x
% your name and the date
y = ???
(This is very simple(the object of this exercise is to get going.)
(b) Now use your cosmx function to compute cosmx(1). Your result should be about -0.4597.
(c) Now use your cosmx function in the same plot sequence as above to plot cosmx and the horizontal axis on the interval -π < x < π. Hint: The horizontal axis is the line y = 0.
  4 Comments
Daniel Shub
Daniel Shub on 26 Oct 2011
Great, so show us the function and then show us what you have done for part c.
mon mon
mon mon on 26 Oct 2011
a)
function y = cosmx ( x )
%y = cosmx(x) computes the difference y=cos(x)-x
% Name & Date
y =cos(x)-x;
end
b) in command window :
cosmx(1)
and it give me the correct result -0.4597

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Accepted Answer

mon mon
mon mon on 26 Oct 2011
plZz help me =,(
  2 Comments
Image Analyst
Image Analyst on 26 Oct 2011
How generous of you to accept your own "answer" instead of someone else who helped you.
Daniel Shub
Daniel Shub on 26 Oct 2011
I think he may have accepted his answer prior to getting any help (with the possible exception of Amardeep's answer). It was accepted before I got involved.

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More Answers (4)

Daniel Shub
Daniel Shub on 26 Oct 2011
ohhh, I know the answer ...
function y = cosmx ( x )
% y = cosmx(x) computes the difference y=cos(x)-x
% your name and the date
y = randn(size(x));
y(x == 1) = -0.4597;
  3 Comments
mon mon
mon mon on 26 Oct 2011
Thanks Daniel ,
But it give me an Error ,too. =(
Daniel Shub
Daniel Shub on 26 Oct 2011
@mon mon, you are right, I made a mistake. It should work now.

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Amardeep
Amardeep on 26 Oct 2011
Create a function which calls cosmx which should look something like. I have left out the plotting functions and the variable arraying to create plottable data.
x = -pi
while x=< pi
y=cosmx(x)
x=x+0.01 (or whatever division resolution you want along the x axis)
end
That should be more than enough to get you along the right lines for part c.
  2 Comments
mon mon
mon mon on 26 Oct 2011
thanXx Amardeep =)
but it give me ERROR =(

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mon mon
mon mon on 26 Oct 2011
my Answer in part (a)
function y = cosmx ( x )
%y = cosmx(x) computes the difference y=cos(x)-x
% Name & Date
y =cos(x)-x;
end
Then part (b) I wrote in command window cosmx(1)
It give me correct >>>> -0.4597
but I do not know part(c) =(
  2 Comments
Daniel Shub
Daniel Shub on 26 Oct 2011
If I asked you to evaluate cosmx at -pi, 0, and pi, how would you do that. What about if I asked you to evaluate cosmx between -pi and pi with steps of 0.01. Do you know how to plot anything?
try
doc plot
mon mon
mon mon on 26 Oct 2011
Daniel
Thank U very much .. =)
I do it .. <3

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mon mon
mon mon on 26 Oct 2011
Thanks All .. =)

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