Over at **Pamibe's she has this very funny post **about graphics she's found that remind her of bloggers.

I made the list and I laughed.

My favorite, however, was the first, Jimbo's and all of you know, Jimbo hates gators.

And for you math geeks that might remember the long problem I did for a girl I tutor in Trig, but don't know why I was off by that small margin, Carl and Peggy having gotten the same answer...

... it is because I changed my cos(-u) to -cos(u) which is incorrect. In my pushing my signs around I erroneously negated it. It should have been +cos(u).

Anyway. Right. I meant to clarify that in the comments of that post and forgot.

Posted by Boudicca at March 4, 2012 11:01 PMComments

It's true; while that is of course not the whole of the man, whenever I see a gator I think of Jim! ;)

In order to move the sign from inside to outside you must multiply by the negative to remove the negative in which case a positive would appear.

Correct?

I think it is because of the symmetry of the function. The same wouldn't hold true of sin(x), since sin(-x) = -sin(x).

Posted by: PeggyU at March 6, 2012 02:42 PMThere are some trigonmetric identities that apply. I botched this one because I had sin on the brain. sin(-x)=-sinx, but cos(-x)=cosx. Cosine functions are what they call 'even' functions. Sine is an odd function.

Posted by: Bou at March 6, 2012 04:12 PM