From: amadd <>
Newsgroups: comp.soft-sys.matlab
Subject: Solving 3 equations in Matlab
Date: Mon, 29 Nov 2010 14:21:12 EST
Organization: The Math Forum
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Hello, I`m having trouble solving equations simultaneously in Matlab. I have three equations and three unknowns. Two equations are algebraic and one is a differential equation. Here are my three equations, any help would be appreciated:

1. (0.3*1.06*3348*Ttank)-(0.3*1.06*3348*Toutc)+(20*200*(sin(t/24*3.14))^8=0

2. (0.041*4418*20)-Toutw*4418*0.041+1000*((Ttank-20)-(Ttank-Toutw))/ln(Ttank-20)/(Ttank-Toutw)

3. 1.06*3348*1.5* dTtank/dt=0.03*1.06*3348*Toutc-0.03*1.06*3348*Ttank-1000*((Ttank-20)-(Ttank-Toutw))/ln(Ttank-20)/(Ttank-Toutw)

t is time and will simulate from 0 until 300. Intial condition for Ttank(0)= 40, so Ttank at 0 is equal to 40. Please I need help urgently. How can this be written in Matlab and how can we plot Toutw against t (time)? I would really appreciate any help.