Question

A little confused about why the absolute value signs are needed after the following...

Answer 1

\[\sqrt{a^2\cos^2x}\]
\[=a|cosx|\]

Answer 2

Because if it's being squared under the root, wouldn't either a negative or +ve value for either a or cosx keep the value under the root positive?

Answer 3

yeah , It may have been -acosx then It was ^2 sqrt

Answer 4

I think you confused between Cos(-x) and Abs

Answer 5

so either acosx or -acosx