The importance of the nonlinear systems due to their common occurrence
in the study of physical phenomena and also the various limitations
posed by the linear systems theory have been the prime reasons for the
studies of nonlinear models as such. The physical situations in which
nonlinear equations arise tend to be highly idealized with the
assumption of constant coefficients. Due to this, much attention has
been paid on study of nonlinear equations with variable coefficients.
This book deals with nonlinear partial differential equations with
variable coefficients representing some interesting physical systems
viz. coupled KdV system, generalized Hirota-Satsuma KdV, variant
Boussinesq, modified Boussinesq and a family of non-evolution equations,
from the view point of their underlying Lie point symmetries and to
obtain their exact solutions. Since the nonlinear systems with variable
coefficients are very difficult to handle, hence this book shall provide
freedom for the researchers to obtain the symmetries and exact solutions
for variable coefficients nonlinear systems and further to simulate the
desired physical situations.