Funny problem. What is cos(pi/2) in matlab?

Hey everyone

While I was programming on matlab I encountered something funny. I don't know if its a bug or what.

Now we all know that cos(pi/2) should be 0. Right??

Now do this:

Code:

`a = 55;`

theta = pi/2;

P = [a1*cos(theta); a1*sin(theta)]

run this, you should get that outcome:

Now here is the messed up part: Input this line now:

Code:

`P(1) %to get the value of first row`

And here is the answer

See it here:

Code:

`>> a = 55`

a =

55

>> theta = pi/2

theta =

1.5708

>> P = [a1*cos(theta); a1*sin(theta)]

P =

0.0000

55.0000

>> P(1)

ans =

3.3678e-015

Why the heck is this happening?? what am I doing wrong??

Please try it on your own matlab. I am using Matlab 7.9 (R2009b)

This should be the simplest code in matlab.

help!