Trig sums

1. Homework Statement

for what values of x is cos(x) - sin(x) < cox(x) + sin(x) where 0 =< x =< 2pi

2. Homework Equations

none.

3. The Attempt at a Solution

I actually drew out the funtions and added them.
In my graphs, I get that:

cos(x) - sin(x) < cos(x) + sin(x) for for 0 =< x =< pi

When I try to show this in Matlab, i ger messy results?

Any ideas?

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There's a simpler way to do it. Did you try algebraically manipulating the equation?

no ... infact, im not sure what you mean?

cos(x) - sin(x) < cos(x) + sin(x)
cos(x) - cos(x) < sin(x) + sin(x)
0 < 2sin(x)
0 < sin(x)

and sin(x) is bigger than zero for 0 =< x =<pi/2

This dosn't seem right to me...

Actually, sin(x)>0 everywhere on the open interval (0,pi).

oh yeah, sorry, i got confused...

so that means that cos(x) - sin(x) is less than cos(x) + sin(x) for (0,pi) ?

Yes. 10char

i don't like this because it dosn't match up with my graphs.

but the math looks right, therefore, their must exist an error in my graphs.

opps, it actually does match with my graphs... :)