Is anyone able to help me here.

As part of an equation we are studying there is a stage where things are "integrated", however I don't understand the process.

Is anyone able to explain, in non math jargon, how the Cos in the following equation is change to Sin during the integration?

Thanks in advance if anyone is able to assist.

http://img134.imageshack.us/img134/3...eenshotwt6.png

Regards,

TK