Hi!

I've got a plain trigonometric equation.

Attachment 25976

π/2 can't be the answer, but Wolfram Alpha has a different opinion.

How is it even possible?

Thanks in advance.

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- Nov 29th 2012, 07:05 AMafterain71Can Wolfram Alpha be wrong?
Hi!

I've got a plain trigonometric equation.

Attachment 25976

π/2 can't be the answer, but Wolfram Alpha has a different opinion.

How is it even possible?

Thanks in advance. - Nov 29th 2012, 07:46 AMemakarovRe: Can Wolfram Alpha be wrong?
I agree: strictly speaking, π/2 is not a solution because tan(π/2) is undefined. Apparently, WolframAlpha simplifies the equation and in the process acquires spurious solutions. The same happens with tan(x)cos(x) = 1.

- Nov 29th 2012, 07:57 AMtopsquarkRe: Can Wolfram Alpha be wrong?
Yes, WA can be wrong. I don't know the extent of it, but see here for a simple integral which it gets wrong. The solution, of course, should be log|x| + C, not log(x) + C.

Always check your answers. Even when using a fancy "calculator" like WA.

-Dan