
Calculus Calculus Math Forum 
 LinkBack  Thread Tools  Display Modes 
November 22nd, 2014, 07:58 AM  #1 
Newbie Joined: Oct 2014 From: los angeles Posts: 6 Thanks: 0  Intersection of a trig funct and polynomial
This is problem #19, section 5.1 on Stewart's 7th edition Calculus. Is asks to sketch the region enclosed by given curves and find it's area $\displaystyle \begin{align*} y&=cos\pi x \end{align*}$ , $\displaystyle \begin{align*} y&=4x^21 \end{align*}$ The integration and finding the area are easy. So is sketching the graphs (that's how i found the intersection points x=+ 1/2). But i'm having trouble solving the equation $\displaystyle \begin{align*} cos\pi x&=4x^21 \end{align*}$ to find the intersection points mathematically. Any suggestions on how to solve this besides Newton's method? Last edited by fsswim11; November 22nd, 2014 at 08:09 AM. 
November 22nd, 2014, 08:30 AM  #2 
Math Team Joined: Jul 2011 From: Texas Posts: 2,949 Thanks: 1555 
by observation, they both have xintercepts at x = 1/2 ... if the functions were different, you'd need an approximation method.


Tags 
funct, intersection, polynomial, trig 
Search tags for this page 
Click on a term to search for related topics.

Thread Tools  
Display Modes  

Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
Solve for x when a trig function equals a polynomial?  chameleojack  Calculus  1  January 11th, 2014 01:02 PM 
making transition from plane trig to spherical trig  cr1pt0  Trigonometry  2  September 5th, 2013 06:11 PM 
union of intersection, intersection of unions  annakar  Applied Math  1  January 7th, 2013 03:16 PM 
Funct of a cx var, cx vars w/ applications  Issler  Calculus  0  March 8th, 2012 03:44 PM 
Divide polynomial without using polynomial identity  condemath  Algebra  3  September 20th, 2011 08:34 PM 