solve for the indicated variable

Question

A=Ws/1-(1+z)^-r    solve for r            /=devided by

Answer 1

A = Ws/(1-(1+z)^-r)

 

A(1-(1+z)^-r) = Ws

 

A - A(1+z)^-r = Ws

 

A(1+z)^-r = A - Ws

 

(1+z)^-r = (A - Ws)/A

 

ln(1+z)^-r = ln[(A-Ws)/A]

 

-rln(1+z) = ln[(A-Ws)/A]

 

r = -ln[(A-Ws)/A]/(ln(1+z))