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

Question

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

anonymous · Answer

I am viewing my own problem now

shadowfiend · Answer

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 $\frac{\pi}{3}$?

anonymous · Answer

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.

shadowfiend · Answer

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