No registration required to write.
Trigonometry equalities, inequalities and expressions  sin, cos, tan, cot
by Guest » Sat Apr 28, 2012 1:05 pm
Hi there I would like to know how to do the following questions without drawing a graph. What is the formula?
The question: Express each of the following in terms of the cosine of another angle between 0° and 180°
a) cos 20°
b) cos 85°
Thank you for any help!

Guest

by Guest » Wed May 02, 2012 3:05 am
cos 60 = cos 3*20
and we can use this formula:

Guest

by Guest » Wed May 02, 2012 3:06 am
I will continue thinking and I will write later.

Guest

Return to Trigonometry  sin, cos, tan, cot, arcsin, arccos, arctan, arccot
Users browsing this forum: No registered users and 1 guest