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## anonymous 5 years ago 2/5=4/5sec(x) which is equivalent to pi/3 but how

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1. anonymous

I am viewing my own problem now

2. shadowfiend

So first off you can move the 4/5 to the other side of the equals sign and get: $\sec x = \frac{\frac{2}{5}}{\frac{4}{5}} = \frac{1}{2}$ We know that $$\sec x$$ is the same as $$\frac{1}{\cos x}$$, which means that: $\frac{1}{\cos x} = \frac{1}{2}$ We can invert both sides and get: $\cos x = 2$ However, this does not make $$x$$ be $$\frac{\pi}{3}$$, so I don't know why you were told it was. Or did I misunderstand what you said about $$\frac{\pi}{3}$$?

3. anonymous

Is it possible that the OP wrote the problem wrong? If s/he had 4/5 = 2/5 sec x, then we have sec x = 2, which is equivalent to cos x = 1/2, and those DO give us x = π/3.

4. shadowfiend

I hope so :) That's roughly what I was noticing.

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