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# where did that come from?

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I was hoping someone would be able to tell me how the 1 - y ... seen @ (1) some how got multiplied by -1 ?, with the result seen @ (2).

Jun 11, 2018

#1
+7373
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To make it less confusing, first know that: $$1-y = -(y-1)$$.

Then, using the property of absolute value function, we have: $$|-x| = |x|$$

It is supposed to be $$-\ln|1-y| + C$$, however, $$-\ln|1-y| = -\ln|-(y-1)| = -\ln|y-1|$$.

Both $$-\ln|1-y| + C$$ and $$-\ln|y-1| + C$$ are correct answers.

Jun 12, 2018
#2
+27567
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The straight lines around 1-y mean "take the absolute value of".  The absolute value of 1-y is the same as that of y-1, so, as Max noted, ln(|y-1|) is the same as ln(|1-y|).

Jun 12, 2018