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View Full Version : Using defination, find tan(_225).


varya
Mar 12, 2011, 01:15 AM

Unknown008
Mar 12, 2011, 02:29 AM
I'm not sure I understand what you mean by 'defination'...

You might want to use the compound angles formula?

\tan (A+ B) = \frac{\tan A + \tan B}{1 - \tan A\tan B}

Put A = 180, B = 45

ebaines
Mar 14, 2011, 07:01 AM
I think what the OP meant is to use the definition:


tan \theta = \frac {sin \theta} {cos \theta}


Finding the sine and cosine of 225 degrees is pretty straight forward - just remember that it's 45 degrees "past" 180, which puts it in the 3rd quadrant. Varya - can you take it from here?