If I have a equation, suppose x.^2+y.^3-10 ; if I put the values of x and y randomly, Can I find the zeroes of this equation at certain values of x and y ? for example x=3 and y=1, there is zero.

If I have a equation, suppose x.^2+y.^3-10 ; if I put the values of x and y randomly, Can I find the zeroes of this equation at certain values of x and y ? for example x=3 and y=1, there is zero. Please help me..

Answer 1

[Doug Hull]

ezplot('x^2 + y^3 - 10')

[Mahak SINGH CHAUHAN]

Dear Matt J; Thanks for this answer. Could I ask one more thing. If I have have more than two variables like x.^2+y.^2-z.^3 ? Is there any way to find ? I know its complicated and may be, I asked a stupid question

Answer 2

[Matt J]

Given a fixed value of x, you can find one corresponding y at which the expression is zero as follows

      x=3;
      f=@(y) x.^2+y.^3-10;

      y_zero = fzero(f, y_guess);

Although, when f() is a polynomial, as in your example, it would be more efficient to use ROOTS instead of FZERO. Also, ROOTS will find you all solutions y for that x, instead of just one.

Similarly for given y, you can find one associated x as follows

      y=1;
      f=@(x) x.^2+y.^3-10;

      x_zero = fzero(f, x_guess);

[Mahak SINGH CHAUHAN]

Thank You very much dear Matt J. Its really helpful.