in the solutions, it was 3e^(s-2) = 9 but where did the e^(2s) go?
answer is s = ln3 + 2
answer is s = ln3 + 2
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When you multiply e^(-s-2) and e^2s , you add the exponents and get
e^(-s-2) * e^2s = e^[ -s - 2 + 2s] = e^(s - 2)
so
3e^(-s-2)e^(2s) = 3e^(s-2)
The problem simplifies to
3e^(s-2) = 9
Divide both sides by 3 to get
e^(s-2) = 3
ln [ e^(s-2)] = ln(3) [the application of the natural log on the left gets rid of the natural base 'e']
s - 2 = ln(3)
s = ln(3) + 2
e^(-s-2) * e^2s = e^[ -s - 2 + 2s] = e^(s - 2)
so
3e^(-s-2)e^(2s) = 3e^(s-2)
The problem simplifies to
3e^(s-2) = 9
Divide both sides by 3 to get
e^(s-2) = 3
ln [ e^(s-2)] = ln(3) [the application of the natural log on the left gets rid of the natural base 'e']
s - 2 = ln(3)
s = ln(3) + 2