What do you mean by Numerical Analysis?
The quantitative approximations to the solutions of mathematical problems including consideration of and bounds to the errors involved.
What do you mean by Algebra?
Algebra is a branch of mathematics dealing with symbols and the rules for manipulating those symbols. In elementary algebra, those symbols (today written as Latin and Greek letters) represent quantities without fixed values, known as variables. Just as sentences describe relationships between specific words, in algebra, equations describe relationships between variables. Example: x+y=3, where x=2. find a value of y. Here, x=2, So, 2+y=3 or, y=3-2 or, y=1
What do you mean by Partial Differential Equation?
A differential equation involving partial derivatives of a dependent variable(one or more) with more than one independent variable is called a partial differential equation.