1. ## help on calculus

Hi all, wondering if one of you kind souls could look at 1c on this site and help teach me why it is the answer that it is...

the question
http://www.math.washington.edu/~m124...1_nichifor.pdf

http://www.math.washington.edu/~m124...chifor_ans.pdf

2. The function is continuous at that point, so all you need to do is substitute in the value of x into the expression.

-Dan

3. yea, but i don't understand the math behind arc cos?

4. Originally Posted by bjorgen
yea, but i don't understand the math behind arc cos?
arccos(2/4) means an angle whose cosine is 2/4, or whose cosine is 1/2.
That angle should be 60 degrees or pi/3 radians.

arcsin(4/5) is an angle whose sine is 4/5.
Etc.