## 26 Reputation

13 years, 94 days

## MaplePrimes Activity

### These are replies submitted by rdkaufman01

Joe,

I see what you mean (to some degree).  But lets take a look at the original post.

> eqn1 := 0.6907 x3 + 0.3336 y3 + 0.6415 z3 - 2.203 = 0:
> eqn2 := cos(theta) x3 + sin(theta) y3 - 1. = 0:
> x3 := solve(eqn2, x3);
1. (sin(theta) y3 - 1.)
- -----------------------
cos(theta)
> y3 := solve(eqn1, y3);
1. (6907. + 6415. z3 cos(theta) - 22030. cos(theta))
- ----------------------------------------------------
-6907. sin(theta) + 3336. cos(theta)

If you did this simple example by hand, it would be easy to obtain:

y3=  [ 2.2030*cos(theta)-0.6415*cos(theta)-0.6907 ] / [0.3336*cos(theta)-0.6907*sin(theta)]

Can't Maple obtain the same answer that you would get by doing this by hand?  The answers are the same, but Maple is multiplying the numerator and denominator by 10000.  If this is related to the floating point numbers that you mentioned, can you suggest how to input the equations to get the hand solution?

-Rich

Joe,

I see what you mean (to some degree).  But lets take a look at the original post.

> eqn1 := 0.6907 x3 + 0.3336 y3 + 0.6415 z3 - 2.203 = 0:
> eqn2 := cos(theta) x3 + sin(theta) y3 - 1. = 0:
> x3 := solve(eqn2, x3);
1. (sin(theta) y3 - 1.)
- -----------------------
cos(theta)
> y3 := solve(eqn1, y3);
1. (6907. + 6415. z3 cos(theta) - 22030. cos(theta))
- ----------------------------------------------------
-6907. sin(theta) + 3336. cos(theta)

If you did this simple example by hand, it would be easy to obtain:

y3=  [ 2.2030*cos(theta)-0.6415*cos(theta)-0.6907 ] / [0.3336*cos(theta)-0.6907*sin(theta)]

Can't Maple obtain the same answer that you would get by doing this by hand?  The answers are the same, but Maple is multiplying the numerator and denominator by 10000.  If this is related to the floating point numbers that you mentioned, can you suggest how to input the equations to get the hand solution?