Math Is Fun Forum

charismath

Member

Registered: 2009-01-23

Posts: 78

cosine inverse of a number>1

I was asked abt the cosine inverse of a number greater than 1.. my reflex answer was obviously that the range of the cosine function is from -1 to +1.. but this was apparently not the expected answer!!:/

would the cosine inverse of a number greater than 1 be a a complex number?

---

Am Stram Gram Spam

<3 GCJLT

luca-deltodesco

Member

Registered: 2006-05-05

Posts: 1,470

Re: cosine inverse of a number>1

The result will indeed be complex, both inverse sine, and inverse cosine can be expanded to all real numbers:

Last edited by luca-deltodesco (2009-02-12 21:02:53)

---

The Beginning Of All Things To End.
The End Of All Things To Come.

charismath

Member

Registered: 2009-01-23

Posts: 78

Re: cosine inverse of a number>1

Ya i think I did this in a maths module last year..  No wonder my lecturer gave me fierce look wen I said I don't know..lol

Thank you for your help:)

---

Am Stram Gram Spam

<3 GCJLT