how do i enter this into my calculator and not get a domain error?

Question

formula: b^2=a^2+c^2-2acCOSB

you have to solve for B. a=4.1764 b=10 c=7. i know you use the inverse cosine but i keep getting a domain error! help please:)

Answer 1

Being in radian mode instead of degree mode (or vice versa) shouldn't have any effect on the domain error. The domain error means that when you tried to take the inverse cosine, the number that you were taking the inverse cosine of was not in the range [-1,1], so you couldn't take the inverse cosine. I don't know what you did wrong, but the correct computation is demonstrated at the site below.

Answer 2

are you in degree mode? and maybe not do the square root till the end

Answer 3

do it one step at a time