Examine the formulas below for a $$9000$ investment. Determine the number of interest periods, the nominal rate and the effective rate.

Round your answer for the effective rate to three decimal places.

a$.A=9000(1+\frac{0\mathrm{.}0458}{4}{)}^{4t}$

$$

b$.A=9000(1+\frac{0\mathrm{.}074}{12}{)}^{12t}$

$$

Nominal rate: $\%$

Effective rate: $\%$

c$.A=9000(1+0\mathrm{.}28{)}^t$

$$

d$.A=9000e^{0\mathrm{.}0643t}$

$$

Nominal rate: $\%$

Effective rate: $\%$