#2**+10 **

Why is arccos (2.3) invalid?

Well here is a rather pale right angled triangle.

AT is the hyotenuse so it is the longest side

Cos A = AB/AT = little side/longest side

How can you divide a little nummber by a big number and get an answer more than 1? You can't!!

That is why cos of an angel must NOT be more than 1

and that is why arccos (2.3 ) is invalid!

Melody Jan 13, 2015

#1**+5 **

The smallest possible value of cosine is -1; the largest possible value is +1. Since 2.3 is not within those values, this arccos of 2.3 is impossible.

geno3141 Jan 12, 2015

#2**+10 **

Best Answer

Why is arccos (2.3) invalid?

Well here is a rather pale right angled triangle.

AT is the hyotenuse so it is the longest side

Cos A = AB/AT = little side/longest side

How can you divide a little nummber by a big number and get an answer more than 1? You can't!!

That is why cos of an angel must NOT be more than 1

and that is why arccos (2.3 ) is invalid!

Melody Jan 13, 2015