Results 1 to 4 of 4

Math Help - matrices with the ti89

  1. #1
    Senior Member
    Joined
    Aug 2009
    Posts
    349

    matrices with the ti89

    ok im trying to do a matrix, or get the determinant from a matrix, but every time i enter it, i get this data type error? can someone tell me why?

    first off im doing a variation of parameter problem and i need to find the eigenvalues of this 2x2 matrix.

    where lambda should be im inserting an x, i figure once i get the result i could solve for x and then get my lamba values.

    the matrix is 3 -5
    3/4 -1

    can someone show me how to enter this into my calc without getting the error messages.

    thanks in advance
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Rhymes with Orange Chris L T521's Avatar
    Joined
    May 2008
    From
    Chicago, IL
    Posts
    2,844
    Thanks
    3
    Quote Originally Posted by slapmaxwell1 View Post
    ok im trying to do a matrix, or get the determinant from a matrix, but every time i enter it, i get this data type error? can someone tell me why?

    first off im doing a variation of parameter problem and i need to find the eigenvalues of this 2x2 matrix.

    where lambda should be im inserting an x, i figure once i get the result i could solve for x and then get my lamba values.

    the matrix is 3 -5
    3/4 -1

    can someone show me how to enter this into my calc without getting the error messages.

    thanks in advance
    On the 89, the general input for a matrix is:

    Code:
    [a,b,c;d,e,f;g,h,i]
    where the semicolons are used to end a row, and this would return

    \begin{bmatrix}a & b & c\\ d & e & f\\ g & h & i\end{bmatrix}

    on your calculator screen. If you want to compute the determinant, then you should use

    Code:
    det([a,b,c;d,e,f;g,h,i])
    and so on for other types of operations.

    So for your example, to find the eigenvalues, you could do it all in one input:

    Code:
    csolve(det([3-x,-5;3/4,-1-x]) = 0,x)
    I put csolve just in case the eigenvalues are complex.

    I hope this helps!

    P.S. You need to make sure that nothing is stored in the variable you're using! Otherwise you'll get an error!! The easiest way to fix that would be to use DelVar "list of variable(s)"
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Senior Member
    Joined
    Aug 2009
    Posts
    349
    thanks alot for that, by the way what is this cssolve command, i never heard of it before.
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Rhymes with Orange Chris L T521's Avatar
    Joined
    May 2008
    From
    Chicago, IL
    Posts
    2,844
    Thanks
    3
    Quote Originally Posted by slapmaxwell1 View Post
    thanks alot for that, by the way what is this cssolve command, i never heard of it before.
    csolve stands for complex solve; i.e. it will return any complex solutions the equation may have. For instance, csolve(x^2+1=0,x) returns x=i or x=-i. However, if you use the regular solve, solve(x^2+1=0,x) returns false, meaning that its not possible to solve for x^2+1 in the real numbers.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. which calculator would better:TI89 or TI-nspire?
    Posted in the Calculators Forum
    Replies: 5
    Last Post: June 12th 2010, 01:10 PM
  2. TI89 Limit
    Posted in the Calculators Forum
    Replies: 1
    Last Post: July 15th 2009, 05:37 AM
  3. Modify TI89 Menus
    Posted in the Calculators Forum
    Replies: 2
    Last Post: May 6th 2009, 04:35 PM
  4. TI84+ better than a TI89 Ti ??
    Posted in the Calculators Forum
    Replies: 3
    Last Post: April 12th 2009, 06:53 PM
  5. [SOLVED] Problem in ti89 programming
    Posted in the Advanced Math Topics Forum
    Replies: 0
    Last Post: March 5th 2008, 12:29 AM

Search Tags


/mathhelpforum @mathhelpforum