**Error: **
(in int) wrong number (or type) of parameters in function iquo

This error is caused by a bug in Release 4 affecting some integrals with nested radicals.

`> `
**int(sqrt(x+sqrt(x)),x);**

Error, (in int) wrong number (or type) of parameters in function iquo

`> `
**int(sqrt(1+y^(-2/3)),y=1..2);**

Error, (in int) wrong number (or type) of parameters in function iquo

The bug is fixed in Release 5.

A work-around is to apply a change of variables, using
**changevar**
from the
**student**
package.

`> `
**with(student,changevar);**

`> `
**changevar(sqrt(x)=t,Int(sqrt(x+sqrt(x)),x),t);**

`> `
**value(");**

`> `
**F:=subs(t=sqrt(x),");**

It's prudent to check an integral by differentiating it and comparing to the original integrand.

`> `
**diff(F,x);**

`> `
**normal("-sqrt(x+sqrt(x)));**

In the second example:

`> `
**changevar(y^(-2/3)=t,Int(sqrt(1+y^(-2/3)),y=1..2),t);**

`> `
**value(");**

A definite integral can be checked by comparing it to a numerical approximation.

`> `
**evalf(");**

`> `
**evalf(Int(sqrt(1+y^(-2/3)),y=1..2));**

Confirming the necessity of checking the result, another bug produces incorrect results for very similar integrals:

`> `
**J:=changevar(y^(-2/3)=t,Int(sqrt(1-y^(-2/3)),y=1..2),t);**

`> `
**value(J);**

`> `
**evalf(");**

The numerical approximation is

`> `
**evalf(Int(sqrt(1-y^(-2/3)),y=1..2));**

In this case the correct result would be produced by combining the fractional powers.

`> `
**Int(3/2*sqrt((1-t)/t^5),t = 1/2*2^(1/3) .. 1);**

`> `
**value(");**

`> `
**evalf(");**

**See also:**

Errors in symbolic integration
,
__int__
,
Integrals involving fractional powers
,
__Numerical Integration__

**Maple Advisor Database**
R. Israel 1998