Question #11be7

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Answer 1 · 2017-03-19T12:49:05

When you are sure of the sign, eg #|x^2|#

Answer 2 · 2017-03-19T12:58:33

This can be done when the argument of the absolute value is non-negative.

Examples:

#5abs(x^2) = 5(x^2)# #" "# (Of course, then parentheses are not needed here.)

#log abs(x^2 + 3) = log(x^2 + 3)#

#sin abs(sqrtx) = sin(sqrtx)#

In the following, the absolute value cannot be replaced:

#abs(x^3 + 5)#

#abs (root(5)x + 7)#

Also

If the argument #u# is non-positive, then #abs(u) = -(u)#

So #log (abs(-x^2+2x-1)) = log(-(-x^2+2x-1)) = log(x^2-2x+1)#