Can we estimate the following relationship using linear regression. Here, $\beta_1, \beta_2 $ and $\beta_3$ are parameters.
$$ y = \beta_1\exp(x) + \beta_2\exp(-x) + \beta_3$$
Can we estimate the following relationship using linear regression. Here, $\beta_1, \beta_2 $ and $\beta_3$ are parameters.
$$ y = \beta_1\exp(x) + \beta_2\exp(-x) + \beta_3$$
This is just multilinear regression.
You have $n$ data points $(x_i,y_i)$. For each point, define $u_i=e^{x_i}$ and $v_i=e^{-x_i}$
$$y = \beta_1\,u + \beta_2\,v + \beta_3$$
Linearity is related to the parameters, not to the functions.