6.12.21 Substituting a subexpression by another expression: algsubs
The algsubs command replaces subexpressions of an expression,
rather than just replace variables.
-
algsubs takes two arguments:
-
expr1=expr2, an
equation between two expressions.
- expr, another expression.
- algsubs(expr1=expr2,expr)
returns the last expression expr with expr1
replaced by expr2.
Examples.
-
Input:
algsubs(x^2 = u, 1 + x^2 + x^4)
Output:
- Input:
algsubs(a*b/c = d, 2*a*b^2/c)
Output:
- Input:
algsubs(2a = p^2-q^2, algsubs (2c = p^2 + q^2, c^2-a^2))
Output: