Unformatted text preview: 1-3x * e 5x ) = ln2e 1-3x + 5x = ln2 + lne 1+2x = ln2 + 1 X = ln2/2 = .3466 [4.6/8] A(t) = A o e-.087t : how long for iodine 131 to decay to 25% of initial amount? 1/4A o =A o e-.087t , therefore 1/4 = e-.087t ln (1/4) = -.087t, therefore T = ln (1/4) / -.087 t = 15.9344...
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- Spring '11
- Calculus, Natural logarithm, Logarithm, Slide rule, Iodine-131, e1-3x * e5x