For each of the following cash flows, decide whether there is a unique yield rate i > ?1? Can you guarantee that the yield rate is positive?

(a) R0 = ?50, 000, R1 = 20, 000, R2 = 10, 000, R3 = 10, 000

(b) R0 = ?50, 000, R1 = ?25, 000, R2 = 30, 000, R3 = 60, 000

(c) R0 = ?50, 000, R1 = 30, 000, R2 = ?10, 000, R3 = 40, 000

(d) R0 = ?50, 000, R1 = 30, 000, R2 = ?30, 000, R3 = 30, 000

(e) R0 = 50, 000, R1 = 30, 000, R2 = 30, 000