# Difference between revisions of "Errata: Last equation in Example 8.6 has sign error in the second term"

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In the last displayed equation of this example, there is a sign error in the term <math>1 + P(s) G_{uy}(s)</math> that appears in the denominator. Because the compensator <math>G_{uy}</math> is in the feedback path and there is ''not'' a negative gain term in the loop, the correct expression is | In the last displayed equation of this example, there is a sign error in the term <math>1 + P(s) G_{uy}(s)</math> that appears in the denominator. Because the compensator <math>G_{uy}</math> is in the feedback path and there is ''not'' a negative gain term in the loop, the correct expression is | ||

<center><amsmath> | <center><amsmath> | ||

− | G_{y r} = \frac{ | + | G_{y r} = \frac{P(s) {\color{blue} G_{ur}(s)}}{1 {\color{blue} -} P(s) G_{uy}(s)} |

− | = \frac{ | + | = \frac{{\color{blue} k_r} (\gamma s + 1)}{s^2 + (k_1 \gamma + k_2) s + k_1}. |

</amsmath></center> | </amsmath></center> | ||

− | Note that the right hand side of the equation is unchanged; the negative sign in the expression for <math>G_{uy}</math> (at the end of the previous page) cancels out. | + | (additional errors reported [[Errata: Last equation in Example 8.6 has errors in numerator expressions|here]] are also shown). Note that the right hand side of the equation is unchanged; the negative sign in the expression for <math>G_{uy}</math> (at the end of the previous page) cancels out. |

}} | }} |

## Latest revision as of 18:09, 28 August 2011

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Location: page 247, line 11

In the last displayed equation of this example, there is a sign error in the term that appears in the denominator. Because the compensator is in the feedback path and there is *not* a negative gain term in the loop, the correct expression is

(additional errors reported here are also shown). Note that the right hand side of the equation is unchanged; the negative sign in the expression for (at the end of the previous page) cancels out.

(Contributed by A. Tits, 4 Nov 2010)