The equation of a plane in three-dimensional space that cuts off equal intercepts of length 1 on the coordinate axes is determined by setting the intercept form of the plane equation:
\( \frac{x}{a} + \frac{y}{b} + \frac{z}{c} = 1 \)
Here, \(a\), \(b\), and \(c\) are the intercepts on the \(x\), \(y\), and \(z\) axes, respectively. For equal intercepts of unit length, we have \(a = b = c = 1\).
Substituting these values into the intercept form gives:
\( \frac{x}{1} + \frac{y}{1} + \frac{z}{1} = 1 \)
Simplifying this, we obtain:
\( x + y + z = 1 \)
Therefore, the equation of the plane that cuts equal intercepts of unit length on each of the coordinate axes is \( x + y + z = 1 \).
The correct answer is the option: x+y+z=1.