My Math Forum Parabola Strange Question
 User Name Remember Me? Password

 Algebra Pre-Algebra and Basic Algebra Math Forum

 June 21st, 2017, 06:56 PM #1 Member   Joined: Apr 2017 From: Canada Posts: 32 Thanks: 2 Parabola Strange Question The following relationship gives the height, "h" in meters, of a soccer ball, as a function of the horizontal distance, d meters, the ball travels until it first hits the ground: h = -0.025(d-20)^2 + 10 Q: If the origin were placed at the vertex of the parabola, what would be the equation of the curve? I have given this some thought and figured that (h,k) of the vertex would double to make (2h,2k) since both the horizontal and vertical distances are increasing by 20 and 10. This would make my new equation: h = -0.025(d-40)^2 + 20 The answer provided is different. Apparently, the new curve would be: h =-0.025(d^2) Could you help me understand?
 June 21st, 2017, 08:05 PM #2 Math Team   Joined: Dec 2013 From: Colombia Posts: 7,313 Thanks: 2447 Math Focus: Mainly analysis and algebra 1) Where is the vertex? $(d,h)=(20,10)$ can you see why? 2) If we translate the plane so that the $(d,h)=(20,10)$ becomes the origin, $(D,H)=(0,0)$, we are saying that $D=d-20$ and $H=h-10$. 3) The equation $h = -0.025(d-20)^2 + 10$ can then be transformed as follows: \begin{align*} h &= -0.025(d-20)^2 + 10 \\ h-10 &= -0.025(d-20)^2 \\ H &= -0.025D^2 \end{align*} Thanks from topsquark and Antoniomathgini

 Tags parabola, question, strange

 Thread Tools Display Modes Linear Mode

 Similar Threads Thread Thread Starter Forum Replies Last Post tankertert Calculus 10 April 30th, 2012 01:15 PM master555 Real Analysis 3 January 23rd, 2012 11:48 PM master555 Real Analysis 1 January 14th, 2012 11:55 AM khyratmath123 Calculus 1 December 15th, 2010 05:45 AM julian21 Algebra 3 November 17th, 2010 08:07 AM

 Contact - Home - Forums - Cryptocurrency Forum - Top

Copyright © 2018 My Math Forum. All rights reserved.