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1. I need to make V1 the subject and im having trouble progressing with it

V1-Vs2/R1 + V1/R2 - IS = 0

I started doing this, is this correct?

R2V1 - R2VS + R1V1 / R1R2 = IS
2. (Original post by lcuckstudent)
I need to make V1 the subject and im having trouble progressing with it

V1-Vs2/R1 + V1/R2 - IS = 0

I started doing this, is this correct?

R2V1 - R2VS + R1V1 / R1R2 = IS
you need to use brackets so that the question is more clear because the way that you have written the question could mean a different few things
3. (Original post by B_9710)
you need to use brackets so that the question is more clear because the way that you have written the question could mean a different few things
(V1-Vs2 / R1)+ (V1 / R2)- (IS)= 0

(R2V1 - R2VS + R1V1)/ (R1R2)= IS

Does this help
4. (Original post by lcuckstudent)
(V1-Vs2 / R1)+ (V1 / R2)- (IS)= 0

(R2V1 - R2VS + R1V1)/ (R1R2)= IS

Does this help
I have attached a picture instead
Attached Images

5. All that you have done so far seems to be correct.
6. (Original post by lcuckstudent)
I have attached a picture instead
Now multiply both sides of the equation by r1r2 and then try and see if you can take out v1 as a common factor which will allow you to further manipulate the equation and make v1 the subject of the equation.
7. (Original post by B_9710)
Now multiply both sides of the equation by r1r2 and then try and see if you can take out v1 as a common factor which will allow you to further manipulate the equation and make v1 the subject of the equation.
I think I may have run away with it to much
Attached Images

8. (Original post by lcuckstudent)
I think I may have run away with it to much
You're right. Now all you need to do is divide by sides by the (r2+r1) and then that's the answer.
9. (Original post by B_9710)
You're right. Now all you need to do is divide by sides by the (r2+r1) and then that's the answer.
Thats what I thought but I have been told the answer is the one attached
Attached Images

10. (Original post by lcuckstudent)
Thats what I thought but I have been told the answer is the one attached
It is exactly the same answer. The answer that you got originally though is in a much nicer form. You can easily show that these 2 fractions are identical.
11. (Original post by B_9710)
It is exactly the same answer. The answer that you got originally though is in a much nicer form. You can easily show that these 2 fractions are identical.
So my final outcome would be the one attached. But when I give the unknown variables a value, the results are not the same as the one I was told was correct
Attached Images

12. (Original post by lcuckstudent)
So my final outcome would be the one attached. But when I give the unknown variables a value, the results are not the same as the one I was told was correct
It doesn't look like you have factorised the numerator correctly. You can only take out a factor of r2 on the numerator.
13. (Original post by B_9710)
It doesn't look like you have factorised the numerator correctly. You can only take out a factor of r2 on the numerator.
so your saying:

Is*R1*R2+R1*Vs

Cant be:

Is*R1(R2+Vs)

???
14. (Original post by lcuckstudent)
so your saying:

Is*R1*R2+R1*Vs

Cant be:

Is*R1(R2+Vs)

???
Yes because Is*R1 is not common to both. You could take out a factor of R1 giving R1(Is*R2 + Vs)
15. (Original post by B_9710)
Yes because Is*R1 is not common to both. You could take out a factor of R1 giving R1(Is*R2 + Vs)
But R1 is common to both R2 and Vs is it not im confused
16. (Original post by lcuckstudent)
But R1 is common to both R2 and Vs is it not im confused
R1 is common. But Is*R1 is not common to both which is what you originally did when you posted the picture.
17. (Original post by B_9710)
R1 is common. But Is*R1 is not common to both which is what you originally did when you posted the picture.
oh right yeah sorry I can see now!!!!

I think its getting late for me, thanks again for your help
18. Ok I've posted it all stow by step because it appears we have both lost our way with this one so I'll just do it from the start.
19. (Original post by B_9710)
Ok I've posted it all stow by step because it appears we have both lost our way with this one so I'll just do it from the start.
Yea great now when I plug this one and the other one with numbers they come out the same

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