Integration cos pi fuction help (deg or rad)?

Hi,

can you please help me?

As a HW assignment we needed to integrate:

cos(3x + 4) dx.....with borders from 0 to pi.(3,14)

1st step: substitute 3x+4 with u.

u=3x+4

du/dx= 3

dx= 1/3du

And change borders: u(0)= 3.0 +4= 4

u(pi)= 3.pi+4

So now our function to integrate is:

cos u 1/3du.....with borders from 4 to 3pi+4

=

1/3[sin u]...borders from 4 to 3pi+4

So now comes my problem and question:

I had my calculator on degrees and got: 1/3(0,232-0,07)= 0,05 as answer

However the answer should be:

1/3(0,757--0,757)= 1/3(1,514)=0.504

Which is what you get when putting the calculator on radians

So My question(Finally)

How should you know whether the calculator should be set to radians or degrees