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jaguar57 February 14th, 2017 10:37 AM

how to simplify this formula?
 
How do you simplify this equation to solve for RPM?
6.089/RPM + 1.98RPM = 14,918
It's part of my new formula for determining peak power RPM by transfer port duration and transfer/boost area. (on a 2 stroke engine)

JeffM1 February 14th, 2017 10:57 AM

Multiply by rpm. You will get a quadratic equation.

deesuwalka February 14th, 2017 09:31 PM

First, make it simple by multiplying each term by $1000$

$\dfrac{6089}{\text{RPM}}\;+\;1980\text{RPM}=14918 000$

Now, multiply each term by RPM

$6089\;+\;1980\text{RPM}^2=14918\text{RPM}$

$1980\text{RPM}^2-14918\text{RPM}+6089=0$

We can observe that it's a quadratic equation So, solve it using quadratic formula, i.e.,

$x=\dfrac{-b\pm\sqrt{b^2-4ac}}{2a}$

skeeter February 15th, 2017 02:53 AM

Quote:

Originally Posted by deesuwalka (Post 562274)
First, make it simple by multiplying each term by $1000$

$\dfrac{6089}{\text{RPM}}\;+\;1980\text{RPM}=14918 000$

Now, multiply each term by RPM

$6089\;+\;1980\text{RPM}^2=\color{red}{14918000RPM }$

$\color{red}{correction}$

Denis February 15th, 2017 06:40 AM

Quote:

Originally Posted by jaguar57 (Post 562242)
6.089/RPM + 1.98RPM = 14,918

x = RPM; rewrite after multiplication by 1000:
6089/x + 1980x = 14918000


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