Finding the minimum length of a median in a triangle

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Homework Help Overview

The discussion revolves around finding the minimum length of a median in a right triangle, specifically focusing on the median AD to side BC. The problem is framed with the condition that the sum of the lengths AB and BC equals 4.

Discussion Character

  • Exploratory, Mathematical reasoning, Assumption checking

Approaches and Questions Raised

  • Participants discuss expressing the lengths of triangle sides in terms of a variable x and explore the implications of taking derivatives of expressions related to the median's length. There are attempts to clarify the relationship between the derivatives of AD and AD², and questions arise about the correctness of previous calculations and assumptions.

Discussion Status

The conversation is active, with participants providing insights and corrections regarding the mathematical expressions involved. Some participants suggest different approaches to taking derivatives and expanding expressions, while others question the implications of their findings. There is no explicit consensus yet, but the dialogue is productive.

Contextual Notes

Participants are navigating through potential typos and clarifications regarding the expressions for the median length, as well as discussing the use of LaTeX for mathematical notation. The original poster has acknowledged a mistake in notation, which has led to further exploration of the problem.

  • #31
Oh, you're correct! I forgot the actual question lol. :) Yes, I was solving for x, not for AD. Many thanks mege and ILS! You two are brilliant!
 
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  • #32
Edit Realised you can't solve it this way, sorry will come back.

Yes, reading your post I was like that...

But thanks for your feedback. As I've said before, you and ILS in the same thread is a total... ;)

So here is the amended version using implicit differentiation.

Let y = AD2

\begin{array}{l}<br /> y = {x^2} + {\left( {4 - 2x} \right)^2} \\ <br /> y = {x^2} + 4{x^2} - 16x + 16 \\ <br /> y = 5{x^2} - 16x + 16 \\ <br /> dy = \left( {10x - 16} \right)dx \\ <br /> \frac{{dy}}{{dx}} = \left( {10x - 16} \right) = 0 \\ <br /> x = 1.6 \\ <br /> \end{array}

Implicit differentiation is a good trick to learn as it can significantly reduce the work.

go well
 

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