sec(x)=sec(y)
tan(x)=tan(y)
though x does not have to be equal to y.
so A=2tan(x);B=2csc(x);C=2sec(x) are all correct! Then the rest of her statements are correct as well.
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那两个式子都不正确,
-柯西-
♀
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01/29/2012 postreply
10:46:11