Mistake in 10.7 84 Answer

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Mistake in 10.7 84 Answer

Adam
The exercise description says:

"Solve the inequality. Express the exact answer in interval notation, restricting your attention to -PI <= x <= PI.

Exercise 84. sin^2(x)<3/4

The answer says: (-2PI/3,-PI/3)U(PI/3,2PI/3)

but it seems not to be correct (see the graph):



So I would expect the answer to be: [-PI, -2PI/3)U(-PI/3, PI/3)U(2PI/3, PI].

Or maybe I'm missing something. I'm referring to the 3rd edition of the book.

Regards
Adam
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Re: Mistake in 10.7 84 Answer

Carl Stitz
Administrator
Thanks very much!

Carl
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Re: Mistake in 10.7 84 Answer

MarkAU
In reply to this post by Adam
Adam, I've just worked this problem and got the same answer as you.  I checked to see if anyone had already questioned the published solution, and was relieved to see that you'd already done so and that my answer wasn't wrong.
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Re: Mistake in 10.7 84 Answer

Carl Stitz
Administrator
Thanks folks!

On Sunday, July 28, 2019, 08:05:25 AM EDT, MarkAU [via Stitz Zeager Open Source Mathematics] <[hidden email]> wrote:


Adam, I've just worked this problem and got the same answer as you.  I checked to see if anyone had already questioned the published solution, and was relieved to see that you'd already done so and that my answer wasn't wrong.


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