Our substitution feature allows you to answer the question "What would this expression, such as \(3+A\), represent if we substituted a different value for \(A\)?" without ever changing the original value of \(A\).
Substitution within a Function
The substitution function, represented by the command ‘with,’ replaces a variable in an expression or function with a constant value, another variable, or a list.
Where would the parabola \(f\left(x\right)=ax^{2}+bx+c\) move if \(b\) was replaced with \(-1\)? Model \(f\left(x\right)\) after substituting \(b\) with \(-1\) to visualize the change.
Where would the polygon be if it was rotated by \(90\) degrees instead of \(45\) degrees? Model the rotation with an angle of \(90\) degrees.
What happens if the center point of the sphere is changed? Model this by substituting your sphere \(S\) with a center at \((2,2,2)\).
Substitution within the Same Expression Line
You can evaluate expressions by substituting variables with constant values in the same line. You can also substitute a variable with another expression, but if that expression depends on a free variable, it will need to be defined separately.
Learn More
Please write in with any questions or feedback to support@desmos.com.