Cubic Formula Proof Step 1: Removing x^2 term via PQ Substitution

in MES Science7 days ago (edited)

▶️ Watch on 3Speak


In this video I go over the first step in deriving the Cubic Formula, which is to eliminate the x2 term from the Cubic Equation by using the PQ Substitution method. This allows us to later apply Vieta's substitution to obtain a quadratic formula, which we can solve. As in the PQ Quadratic Formula method, I set x = y + k and then expand the powers and select a k value such that the x2 terms get eliminated. Then rearranging and defining p and q as the terms for the coefficients of the x1 and x0, we obtain the PQ version of the Cubic Equation.

2 Step 1 Remove Square Power PQ.jpeg

Time stamps

  • Step 1: Get rid of x2 term using PQ Substitution in order to later apply Vieta's substitution to get a quadratic formula: 0:00
  • Applying PQ substitution to cubic equation by letting x = y + k: 1:46
  • Expanding out the y2 terms only: 3:20
  • Equate y2 terms to equal zero and solve for k: 5:10
  • Recap of Pascal's Triangle: https://en.wikipedia.org/wiki/Pascal%27s_triangle 6:00
  • Plugging in our k to cancel out terms and rearrange equation: 7:43
  • Divide new Cubic Equation by a: 13:40
  • Substitute p and k to obtain the new PQ Cubic Equation: 14:45

Notes and playlists


Become a MES Super Fan! https://www.youtube.com/channel/UCUUBq1GPBvvGNz7dpgO14Ow/join

DONATE! ʕ •ᴥ•ʔ https://mes.fm/donate

SUBSCRIBE via EMAIL: https://mes.fm/subscribe

MES Links: https://mes.fm/links



MES Truth: https://mes.fm/truth Official Website: https://MES.fm Hive: https://peakd.com/@mes

Email me: [email protected]

Free Calculators: https://mes.fm/calculators




BMI Calculator: https://bmicalculator.mes.fm Grade Calculator: https://gradecalculator.mes.fm Mortgage Calculator: https://mortgagecalculator.mes.fm Percentage Calculator: https://percentagecalculator.mes.fm

Free Online Tools: https://mes.fm/tools

iPhone and Android Apps: https://mes.fm/mobile-apps


▶️ 3Speak

Sort:  
 6 days ago  

!summarize

 6 days ago  

!summarize

You don't have an active Creator Subscription to @mightpossibly. Subscribe for immediate access

 6 days ago  

@mightpossibly I keep getting this error, even though I continued my subscription 7 hours ago. Would you know why?

image.png

Ahh, something is definitely not working correctly with this. Apologies, I will look into it. Your sub is active now and I added a couple of days for your trouble

 6 days ago  

Amazing thanks! Yeah hopefully it gets fixed up.

I will figure it out, no worries 👍

 7 days ago  

!summarize

You don't have an active Creator Subscription to @mightpossibly. Subscribe for immediate access

 7 days ago  

!summarize

You don't have an active Creator Subscription to @mightpossibly. Subscribe for immediate access