  We investigate a form of $ f(R) = {R^{1+\delta}}/{R_c^{\delta}}$ and study
the viability of the model for inflation in the Jordan and the Einstein frames.
This model is further analysed by using the power spectrum indices of the
inflation and the reheating temperature. During the inflationary evolution, the
model predicts a value of $\delta$ parameter very close to one ($\delta=0.98$),
while the reheating temperature $T_{re} \sim 10^{17}$ GeV at $\delta=0.98$ is
consistent with the standard approach to inflation and observations. We
calculate the slow roll parameters for the minimally coupled scalar field
within the framework of our model. It is found that the values of the scalar
spectral index and tensor-to-scalar ratio are very close to the recent
observational data, including those released by Planck 2018. We also show that
the Jordan and the Einstein frames are equivalent when $\delta \sim 1 $ by
using the scalar spectral index, tensor-to-scalar ratio and reheating
temperature.
