NSolve Command

CAS Syntax

This command is only available in the CAS View.

NSolve( <Equation> )

Attempts (numerically) to find a solution for the equation for the main variable. For non-polynomials you should always specify a starting value (see below).

Example:

NSolve[x^6 - 2x + 1 = 0] yields {x = 0.51, x = 1}.

NSolve( <Equation>, <Variable> )

Attempts (numerically) to find a solution of the equation for the given unknown variable. For non-polynomials you should always specify a starting value (see below).

Example:

NSolve[a^4 + 34a^3 = 34, a] yields {a = -34, a = 0.99}.

NSolve( <Equation>, <Variable = starting value> )

Finds numerically the list of solutions to the given equation for the given unknown variable with its starting value.

Examples:

• NSolve[cos(x) = x, x = 0] yields {x = 0.74}
• NSolve[a^4 + 34a^3 = 34, a = 3] yields {a = 0.99}.

NSolve( <List of Equations>, <List of Variables> )

Attempts (numerically) to find a solution of the set of equations for the given set of unknown variables.

Example:

NSolve[{pi / x = cos(x - 2y), 2 y - pi = sin(x)}, {x = 3, y = 1.5}] yields {x = 3.14, y = 1.57}.

Note:

• If you don't give a starting point like a=3 or {x = 3, y = 1.5} the numerical algorithm may find it hard to find a solution (and giving a starting point doesn't guarantee that a solution will be found)
• The number of decimals depends on the choosen in global rounding.
• NSolve won't work for functions that are asymptotic to the x-axis or other extreme examples. They can often be reformulated though.
• NSolve will work only if the function is continuous!
• See also Solve Command and NSolutions Command.