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The Maxima on-line user's manual

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Assume Calculator

Assume

Function: assume (<pred_1>, ..., <pred_n>) Adds predicates <pred_1>, ..., <pred_n> to the current context. If a predicate is inconsistent or redundant with the predicates in the current context, it is not added to the context. The context accumulates predicates from each call to assume.

assume(n>0);
integrate(x^n,x);

assume returns a list whose elements are the predicates added to the context or the atoms redundant or inconsistent where applicable.

The predicates <pred_1>, ..., <pred_n> can only be expressions with the relational operators < <= equal notequal >= and >. Predicates cannot be literal equality = or literal inequality # expressions, nor can they be predicate functions such as integerp.

Compound predicates of the form <pred_1> and ... and <pred_n> are recognized, but not <pred_1> or ... or <pred_n>. not <pred_k> is recognized if <pred_k> is a relational predicate. Expressions of the form not (<pred_1> and <pred_2>) and not (<pred_1> or <pred_2>) are not recognized.

Maximas deduction mechanism is not very strong; there are many obvious consequences which cannot be determined by is. This is a known weakness.

assume does not handle predicates with complex numbers. If a predicate contains a complex number assume returns inconsistent or redunant.

assume evaluates its arguments.

See also is, facts, forget, context, and declare.

Examples:

          (%i1) assume (xx > 0, yy < -1, zz >= 0);
          (%o1)              [xx > 0, yy < - 1, zz >= 0]
          (%i2) assume (aa < bb and bb < cc);
          (%o2)                  [bb > aa, cc > bb]
          (%i3) facts ();
          (%o3)     [xx > 0, - 1 > yy, zz >= 0, bb > aa, cc > bb]
          (%i4) is (xx > yy);
          (%o4)                         true
          (%i5) is (yy < -yy);
          (%o5)                         true
          (%i6) is (sinh (bb - aa) > 0);
          (%o6)                         true
          (%i7) forget (bb > aa);
          (%o7)                       [bb > aa]
          (%i8) prederror : false;
          (%o8)                         false
          (%i9) is (sinh (bb - aa) > 0);
          (%o9)                        unknown
          (%i10) is (bb^2 < cc^2);
          (%o10)                       unknown

There are also some inexact matches for assume. Try ?? assume to see them.

(%o1)                                true
(%i2) 

Assume Example

Related Examples

assume-integrate

integrate(ln(4*x^2+1)...

f(x):='integrate(ln(4...

assume(y>0);

Calculate

assume-integrate-sqrt

assume(t>0);

integrate(s*s/sqrt(t-...

assume(x>0);

Calculate

assume-diff-integrate-plot2d-sin-subst
plot2d([eq3,2*sin(a)],[a,0,4*%pi]);

eq1:sin(x);

assume(a>=0,b>=0);

eq2:integrate(eq1,x,a...

Calculate

assume-diff-plot2d-solve
plot2d(f(x),[x,-5,5]);

assume(x>=1);

f(x):=5/(2*x^2+1);

solve(f(x)=y,x);

Calculate

assume-integrate-ratsimp-sin

assume(n>0);

assume(L>0);

f(x):= sin(n*%pi*x/L)...

Calculate

assume-diff-ev-integrate-plot2d-sin
plot2d ([yexa(x),yvar(x),yvar2(x)], [x, 0, L],[legend,"exacta","variacional 1 orden","variacional 2 orden"],[style,lines]);

/*Solución exacta*/ye...

/*Aproximación de pri...

dy(x):=diff(y(x),x);

Calculate

assume-is

assume(x<0);

assume(y<0);

f(x,y):= 3*x*y;

Calculate

assume-integrate-log

/* vz (superposition)...

assume(k < 1);

Vz: 0.25*(1 - (xi^2) ...

Calculate

assume-diff-factor-integrate-log-ratsimp

/* vz (superposition)...

assume(k < 1);

Vz_nondim: (G)*(1 - (...

Calculate

assume-inf-limit-taylor-tlimit

limit((1+1/n)^n,n,inf);

tlimit((1+1/n)^n,n,inf);

assume(u>0);

Calculate