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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-factor-rat

rat(((x^4-x^3-11*x^2+...

rat((2-x)/(x+1))*((3*...

rat(((x^3+2*x^2+4*x+8...

Calculate

at-rat

rat(((x^4-x^3-11*x^2+...

rat((2-x)/(x+1))*((3*...

rat(((x^3+2*x^2+4*x+8...

Calculate

at-eigenvalues-invert-jacobian

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

B: jacobian ([1/r*Ih,...

C: invert (B);

Calculate

at-cos

eq1:y-e^(-a*t)-b*sen(t);

eq2:a*e^(-at)-b*cos(t);

eq1*eq2*2;

Calculate

at-rat

rat((2/(1-x)^2+1/(x^2...

rat(2/(1-x)^2+1/(x^2-...

rat((2/(1-x)^2+1/(x^2...

Calculate

at-diff-sqrt

P:4*X^4+2^(7/2)*sqrt(...

P1:diff(P,X);

at(P,[x=2]);

Calculate

at-diff-ev-exp

g(x) := x + exp(-alph...

k1 : 8.0000e+03;

k2 : 1.0000e+00;

Calculate

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

f:a0+a1*s^2+a2*s^4;

cond1:at(f,s=1)=0;

cond2:at(diff(f,s),s=...

Calculate

at-diff-linsolve-quad_qags-subst

f:a0+a1*s^2+a2*s^4;

cond1:at(f,s=1)=0;

cond2:at(diff(f,s),s=...

Calculate

at-diff-factor-sqrt

f(x,y,A) := sqrt((1+x...

f40(x,y,A) := diff(f(...

f31(x,y,A) := diff(di...

Calculate