You are here:
- Home
- Science
- Mathematics
- Advanced Math
- Prove the identities
Advanced Math/Prove the identities
Advertisement
Question
How do i prove this identity?
cotx - tanx = 2cosx * cscx - secx * cscx
if by this you mean
2cos(x)csc(x) - sec(x)csc(x)
2cos(x)(1/sin(x)) - (1/cos(x))(1/sin(x))
(2cos(x)/sin(x)) - (1/(cos(x)sin(x))
(2cos(x)^2 - 1)/sin(x)
cos(2x)/(sin(x)cos(x))
------------------
cot(x) - tan(x)
(cos(x)/sin(x)) - (sin(x)/cos(x))
(cos(x)^2 - sin(x)^2)/(sin(x)cos(x))
cos(2x)/(sin(x)cos(x))
so
2cos(x)csc(x) - sec(x)csc(x) = cot(x) - tan(x)
more info found at www.math.com/tables/trig/identities.htm
Related Articles
Advanced Math
Answers by Expert:
Sherman D.
Expertise
I can answer questions dealing in mathematics of all kinds except for Physics and Calculus, but i can answer questions in Pre-Calculus and Chemistry. I can also answer questions in Recipes of all kinds. I can find games cheats/walkthroughs, but i can`t find a specific game online or offline. I can also do history and recipes for alcoholic beverages.
Experience
Mathematics, Recipes, History, and Games.
Education/Credentials
High School graduated. I graduated with honors, and i was in Beta Club for a year and a half.
Awards and Honors
Principle's list and A and B honor roll in high school only.
©2012 About.com, a part of The New York Times Company. All rights reserved.