Maths question RE summation symbol
Maths question RE summation symbol
(OP)
Hi everyone,
I'm integrating a PV diagram. I have successfully done the integration, but now just want to show that the final value is the sum of all the values collected for each crank angle, from let's say for instance 1 degree to 180 degrees.
I could just not bother using the symbol and just explain in words, but I'd like to know how to properly use the summation symbol. The image below is my guess at how I could use it in this situation. Please tell me if this is incorrect ! Thanks

I'm integrating a PV diagram. I have successfully done the integration, but now just want to show that the final value is the sum of all the values collected for each crank angle, from let's say for instance 1 degree to 180 degrees.
I could just not bother using the symbol and just explain in words, but I'd like to know how to properly use the summation symbol. The image below is my guess at how I could use it in this situation. Please tell me if this is incorrect ! Thanks





RE: Maths question RE summation symbol
1) you've not done the integral, you've done a step-by-step summation of values by crank angle
2) you want to show THAT in equation form
My proposal is that you want Sum(theta from 1 to 180)[P(theta)*(V(theta)-V(theta-1)]
RE: Maths question RE summation symbol
RE: Maths question RE summation symbol
The image below is a screenshot of the spreadsheet:
RE: Maths question RE summation symbol
RE: Maths question RE summation symbol
So, lose the algebraic integral sign, and add a subscript theta to the P. Change the d to a small delta.
So it should be
sigma super 180 sub theta=0 P sub theta dot small_delta V
Cheers
Greg Locock
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RE: Maths question RE summation symbol
RE: Maths question RE summation symbol
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RE: Maths question RE summation symbol
RE: Maths question RE summation symbol
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