Solve for K Wt=Wi*e^-kt
I assume: W(t)=W(i)⋅e−kt
W(t)=W(i)⋅e−kt|:W(i)W(t)W(i)=e−kt|lnln(W(t)W(i))=ln(e−kt)ln(W(t))−ln(W(i))=−kt⋅ln(e)|ln(e)=1ln(W(t))−ln(W(i))=−kt|⋅(−1)−ln(W(t))+ln(W(i))=ktkt=−ln(W(t))+ln(W(i))kt=ln(W(i))−ln(W(t))|:tk=ln(W(i))−ln(W(t))t
