## 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..

Asked by Mahak SINGH CHAUHAN

### Mahak SINGH CHAUHAN (view profile)

on 11 Mar 2014
Latest activity Edited by Mahak SINGH CHAUHAN

### Mahak SINGH CHAUHAN (view profile)

on 11 Mar 2014
Accepted Answer by Doug Hull

### Doug Hull (view profile)

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..

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Answer by Doug Hull

### Doug Hull (view profile)

on 11 Mar 2014

ezplot('x^2 + y^3 - 10') #### 1 Comment

Mahak SINGH CHAUHAN

### Mahak SINGH CHAUHAN (view profile)

on 11 Mar 2014
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 by Matt J

on 11 Mar 2014
Edited by Matt J

### Matt J (view profile)

on 11 Mar 2014

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);

#### 1 Comment

Mahak SINGH CHAUHAN

### Mahak SINGH CHAUHAN (view profile)

on 11 Mar 2014
Thank You very much dear Matt J. Its really helpful.