y=cot-1(-.92170128)

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- Aug 23rd 2008, 05:04 PMneeInverse Circular Function, help!!!
y=cot

**-**1(-.92170128)

- Aug 23rd 2008, 05:14 PMSpec
What's the question exactly?

- Aug 23rd 2008, 05:24 PMnee
According to the text the answer should come up to

**2.3154725**in radian mode.

The text states: "We take the inverse tangent of the reciprocal to find the inverse cotangent".

I therefore punch in:

tan-1(1/-0.92170128)

like the examples show me but I get:

-0.826120119 - Aug 23rd 2008, 05:39 PMSpec
You were using the correct method: $\displaystyle cot^{-1}(z) = tan^{-1}(\frac{1}{z})$

The book's answer is $\displaystyle -0.826120119 + \pi$

I should probably mention that they've given this answer because arccotangent's range is $\displaystyle 0 < y < \pi$ - Aug 23rd 2008, 05:43 PMnee
OK I just fugured it out:

In degree mode I punched in:

tan-1(1/-0.92170128)

= -47.33319621

-47.33319621 + 180 (which is ∏ radians)

= 132.6668038

132.6668038/180

= 0.737037799

0.737037799 x ∏

= 2.31572534

but I can't fugure out how to get the answer strait into radians? - Aug 23rd 2008, 05:45 PMnee
Oh ok. Thanks Spec, I was almost there.

nee