How do you do a double integral on the TI89?I’ve searched all over and can’t find out how!I can do singles.

August 11th, 2009
Renee R asked:


I keep getting “too few arguments” when I try to “nest” the integrals, but I cannot find anything online about this or in the manual. Please help!

2 Responses to “How do you do a double integral on the TI89?I’ve searched all over and can’t find out how!I can do singles.”

  1. Dan Says:
    August 14th, 2009 at 1:03 am

    lets say we want to find the integral of:

    ∫ ∫ x²y + y² + sin(y) dxdy

    type this exactly as i put it:

    ∫( ∫(x^2 * y + y^2 + sin(y), x), y) and hit enter. you should get:

    -cos(y)*x + (y^3 x) / 3 + (y^2 x^3) / 6

    hope this helped!

  2. Amy J Says:
    August 16th, 2009 at 7:20 am

    You have to next the integrals. Just make sure you add all of your arguments. For example, let’s say you need the double integral below without any limits of integration:

    int int 2xy dx dy

    Type as follows:
    int(int(2*x*y,x),y)
    Make sure the inner integral has a comma and then x because it is with respect to x and then OUTSIDE the parenthesis you have another comma and a y because the outside integral is with respect to y.

    Now, if you instead wanted to take an integral with limits of integration like:

    int int 2*x*y dx dy where the inner integral is from x=0 to x=y-1 and the outer integral is from y=2 to y=3

    Type int(int(2*x*y,x,0,y-1),y,2,3) in the TI89. Hope this makes sense.