Difference between revisions of "NSolve Command"
From GeoGebra Manual
m |
(or other extreme examples) |
||
Line 20: | Line 20: | ||
* 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) | * 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 [[Options Menu#Runding|global rounding]]. | * The number of decimals depends on the choosen in [[Options Menu#Runding|global rounding]]. | ||
− | * NSolve won't work for functions that are asymptotic to the x-axis. They can often be reformulated though. | + | * 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! | * NSolve will work only if the function is continuous! | ||
* See also [[Solve Command]] and [[NSolutions Command]]. | * See also [[Solve Command]] and [[NSolutions Command]]. | ||
</div>}} | </div>}} |
Revision as of 14:02, 5 February 2016
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.