Trig.

Would be most grateful for the following proofs:

Cos (180- Theta)= - Cos Theta &

Sin (180-Theta)= Sin Theta

Many thanks

Mike

Refer to the Unit Circle, and the definition and development of the trigonometric functions. It will be there, right before your beady little eyes!

Thanks for the pointer but the sites I have consulted don't give the "nuts and bolts" explanation for obtuse angles.

Mike

Sites? How about something really clever,.... like a text-book!

Define, for yourself, the sine and cosine functions. (They're in the book! You do have a text-book, don't you?) Then take a look at a "Unit Circle," such as this one:




Is it evident now, or do you require further guidance?

I genuinely very much appreciate your reply but, may I, with the greatest respect, prevail upon you to show slightly more charity with those of us for whom mathematics does not come as naturally and spontaneously as it obviously does for you!

Mike

wow and this is why I decided not to take trig next year.

what!? I admit, trig is not fun but Calculus is awsome! Take trig!