# C4 differential Equations Help!!Watch

#1
i understand that if you have

dy/dx = xy this becomes: 1/y dy/dx = x

no problem here.

However, when they start involving number as well as constants i don't know were to move things

for example:

-10 dv/dx = v - 200

and

dv/dt = 1000/(2t+1)^2

could someone please clarify what has to be done when they involve constants combined with numbers
0
7 years ago
#2
The first one, you can divide both sides by (v-200) and multiply both sides by dx so you have

-10/(v-200) dv = 1 dx

Then divide both by -10 so you have 1/(v-200) dv = -1/10 dx then you can integrate.

On the second one can you not just multiply both sides by dt and then integrate so you would have 1 dv = 1000/(2t+1)^2 dt

Which would be v = -500/(2t +1) + c?

PS - I'm taking my c4 exam in June
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