Symbolic functions represent math functions. Use symbolic functions for differentiation,
integration, solving ODEs, and other math operations. Create symbolic functions by using
syms.
Create a symbolic function f with variables x and
y by using syms. Creating f
automatically creates x and y.
syms f(x,y)
Assign a mathematical expression to f.
f(x,y) = x^2*y
f(x, y) = x^2*y
Find the value of f at (3,2).
f(3,2)
ans = 18
Symbolic functions accept array inputs. Calculate f for multiple values
of x and y.
xVal = 1:5; yVal = 3:7; f(xVal,yVal)
ans = [ 3, 16, 45, 96, 175]
You can differentiate symbolic functions, integrate or simplify them, substitute their
arguments with values, and perform other mathematical operations. For example, find the
derivative of f(x,y) with respect to x. The result
dfx is also a symbolic function.
dfx = diff(f,x)
dfx(x,y) = 2*x*y
Calculate df(x,y) at x = y + 1.
dfx(y+1,y)
ans = 2*y*(y + 1)
If you are creating a constant function, such as f(x,y) = 1, you must
first create f(x,y). If you do not create f(x,y), then
the assignment f(x,y) = 1 throws an error.