Solving an equation with undefined value

[AC_10490989]

Hey guys,

I'n new to PTC . Trying to get away with solving equations. I'm having some issues heres, if someone could help that would be very appreciated . 

I want to solve the following equation : 

Y=x(R2/(R1+R2)

Where : 

Y=0.8,X=12,R1=10

R2=Unknown

So I type the following on mathcad : 

R1:= 10 

X:=12

Y:=0.8

Y=x(R2/(R1+R2) => Solve,R2

Unfortunately it keeps saying that R2 is undefined . Does someone know what's going on here ?

Thanks a lot guys.

[Werner_E · Accepted solution]

Always attach your worksheet, too. Not just the pic.

You have to use the boolean/comparison "equal to" and not the "normal" one which is for numeric evaluation.

As you are only after a numeric result you may also use a numeric solve block or the numeric "root" function instead of the symbolic "solve".

Worksheet in format P6 attached

[AC_10490989]

Hi 24-Ruby IV,

Thanks a lot for your proposed solution.

Best regards

[Werner_E]

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@AC_10490989 wrote:

Hi 24-Ruby IV,

Thanks a lot for your proposed solution.

Best regards

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You are welcome!

BTW, "24-Ruby IV"  is an expression of a rather stupid and peculiar ranking system which is implemented here in the forum, its not my nickname (like yours is not "2-Guest")  😉