MHB Circular Functions: Sec-1(-rad(2))

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The discussion centers on evaluating Sec-1(-rad(2)), with confusion surrounding the term "rad." Participants clarify that "rad" could refer to either "-2 radians" or "radical(2)" (√2). They emphasize using the relationship sec(x) = 1/cos(x) to find the corresponding angle. For -√2, the cosine value is -1/2, leading to the conclusion that the angle can be found without a calculator. The conversation highlights the importance of precise terminology in mathematical expressions.
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Sec-1(-rad(2))
 
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rebecca120 said:
Sec-1(-rad(2))

Please supply more context, like the question as asked.

The argument of \( \rm{asec} \) is just a number so I don't see what \( \rm{rad} \) is doing in your question.

CB
 
rebecca120 said:
Sec-1(-rad(2))
-rad(2)? Do you mean "- 2 radians"? Use the fact that sec(x)= 1/cos(x) and use a calculator (making sure it is in "radian" mode) to find cos^{-1}(-1/2).

Or do you mean "radical(2)" as in "\sqrt{2}"? \frac{1}{\sqrt{2}}= \frac{\sqrt{2}}{2} so find cos^{-1}\left(-\frac{\sqrt{2}}{2}\right). You shouldn't need a calculator for that.
 
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