My Math Forum Trigonometric Ratios

 Trigonometry Trigonometry Math Forum

 November 12th, 2012, 07:13 AM #1 Senior Member   Joined: Sep 2011 Posts: 395 Thanks: 0 Trigonometric Ratios The tables, or calculator, clearly shows that $\cos\pi$ or $\cos180^{\circ}=-1$. Is the books answer incorrect or did I miss something? Many thanks. Q. Using Mathematics Tables, write down the solutions of the equation $\cos\theta=1$ in the interval $0\leq\theta\leq2\pi$. Attempt: $\cos\theta=1=0^{\circ}&360^{\circ}=0&2\pi=$ Ans. $0&\pi&2\pi$
 November 12th, 2012, 10:52 AM #2 Senior Member     Joined: Jul 2010 From: St. Augustine, FL., U.S.A.'s oldest city Posts: 12,211 Thanks: 521 Math Focus: Calculus/ODEs Re: Trigonometric Ratios Apparently, the book intended: $\cos^2(\theta)=1$ or $|\cos(\theta)|=1$ either that or the given solution is just wrong.
 November 12th, 2012, 10:56 AM #3 Senior Member   Joined: Sep 2011 Posts: 395 Thanks: 0 Re: Trigonometric Ratios Thanks for clearing that up. Much obliged.

 Tags ratios, trigonometric

 Thread Tools Display Modes Linear Mode

 Similar Threads Thread Thread Starter Forum Replies Last Post linhbui Elementary Math 4 August 22nd, 2012 06:24 AM IHateFractions Trigonometry 7 December 10th, 2011 02:32 AM jatt-rockz Trigonometry 5 November 10th, 2011 12:17 PM MathematicallyObtuse Algebra 3 January 9th, 2011 08:07 AM metallic.panda Algebra 2 August 11th, 2009 12:12 AM

 Contact - Home - Forums - Cryptocurrency Forum - Top