My Math Forum Integral with trig identity (help)

 Calculus Calculus Math Forum

 November 4th, 2014, 03:46 PM #1 Newbie   Joined: Oct 2014 From: California Posts: 5 Thanks: 0 Integral with trig identity (help) $\displaystyle \int \sqrt{40+6x-x^2}dx$ So I solved it out and managed to get the answer using (x-3) = 7sin(theta) $\displaystyle \frac{49}{2}(\theta+\frac{sin(2\theta)}{2})+C$ However, using the double angle identity, does the answer above equal: $\displaystyle \frac{49}{2}(\theta+sin\theta cos\theta)+C$ I punched both equations to my calculator and Symbolab a bunch of times and the definite answers seem to be different. I must be missing something . Thanks in advance!!!
 November 4th, 2014, 04:17 PM #2 Math Team     Joined: Jul 2011 From: Texas Posts: 3,016 Thanks: 1600 I graphed both on my TI-83 (assuming C = 0 for both) ... their graphs coincide. Thanks from jouishishi

 Tags identity, integral, trig

 Thread Tools Display Modes Linear Mode

 Similar Threads Thread Thread Starter Forum Replies Last Post WWRtelescoping Complex Analysis 3 February 9th, 2014 09:49 AM najaa Trigonometry 6 May 14th, 2012 03:30 PM Aiyla Trigonometry 2 February 14th, 2012 08:09 AM jsmith613 Algebra 25 January 6th, 2011 07:52 PM Stringbags Algebra 2 March 22nd, 2009 03:39 PM

 Contact - Home - Forums - Cryptocurrency Forum - Top