# How do you evaluate #cos A = 0.7431#?

##### 2 Answers

#### Explanation:

#"given "cosA=0.7431#

#"then "angleA=cos^-1(0.7431)=42^@#

#### Explanation:

Cosines, unlike sines, uniquely determine a triangle angle between

But we're not given any such constraint here. As far as we know,

What's important to remember is the general solution to

The principal value of the inverse cosine gives us a particular solution and we apply the recipe to turn it into the general solution.

That's the exact, general answer. It gives all the

Now we're supposed to get out our calculator and evaluate the inverse cosine. I don't like that part. I got a nice exact answer here and I have to muck it up.