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The Maxima on-line user's manual

Algebra Calculator

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At Calculator

At

Function: at (<expr>, [<eqn_1>, ..., <eqn_n>])

f:5*4.57+3;
at(f,x=4,57);
df:diff(f,x);
at(df,x=4.57);
plot2d(df,[x,0,1])

Function: at (<expr>, <eqn>) Evaluates the expression <expr> with the variables assuming the values as specified for them in the list of equations [<eqn_1>, ..., <eqn_n>] or the single equation <eqn>.

If a subexpression depends on any of the variables for which a value is specified but there is no atvalue specified and it cant be otherwise evaluated, then a noun form of the at is returned which displays in a two-dimensional form.

at carries out multiple substitutions in series, not parallel.

See also atvalue. For other functions which carry out substitutions, see also subst and ev.

Examples:

          (%i1) atvalue (f(x,y), [x = 0, y = 1], a^2);
                                          2
          (%o1)                          a
          (%i2) atvalue (diff (f(x,y), x), x = 0, 1 + y);
          (%o2)                        @2 + 1
          (%i3) printprops (all, atvalue);
                                          !
                            d             !
                           --- (f(@1, @2))!       = @2 + 1
                           d@1            !
                                          !@1 = 0

2 f(0, 1) = a

          (%o3)                         done
          (%i4) diff (4*f(x, y)^2 - u(x, y)^2, x);
                            d                          d
          (%o4)  8 f(x, y) (-- (f(x, y))) - 2 u(x, y) (-- (u(x, y)))
                            dx                         dx
          (%i5) at (%, [x = 0, y = 1]);
                                                   !
                        2              d           !
          (%o5)     16 a  - 2 u(0, 1) (-- (u(x, y))!            )
                                       dx          !
                                                   !x = 0, y = 1

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

(%o1)                                true
(%i2) 

At Example

Related Examples

at-cos-diff-expand-linsolve-pi-quad_qags-sin-subst

sd: 0.6;

f0: expand(s^2*(a0 + ...

c0: at(f0,s=1)=%pi;

Calculate

at-rectform

at ((1/(c*(x+%i*y) + ...

Calculate

at-block-equal-limit-makelist-plot2d
plot2d((x+1)/(x-1), [x, -10, 10], [y, -100, 100], [gnuplot_preamble, "set xtics 1"]);

continuous_at(expr, v...

continuous_at((x+1)/(...

plot2d((x+1)/(x-1), [...

Calculate

at-diff

diff((1+e^at)/(1-e^at...

Calculate

at-solve-subst

z: V1*p1/T1 = V2*p2/T2;

isop: z, p1=1, p2=1;

isoV: z, V1=1, V2=1;

Calculate

at-cosh-diff-log

at(diff(arccos(1/cosh...

Calculate

at-num-numer-rat

rat(0.1234);

rat(0.12345);

num(rat(0.12345))/3, ...

Calculate

at-expand-subst

expr : z^3 + (a1*z + ...

expr : subst (expr, w...

expand (at (expr, [w ...

Calculate

at-cos-numer-sin

at (2 * cos (%pi*s/2)...

Calculate

at-eigenvalues-invert-jacobian

A: jacobian ([a*If*Sh...

B: jacobian ([gh*Ih, ...

C: invert (B);

Calculate