December 19, 2018, 09:54 PM
zipridersonHigh School Math Help
3^2 = 1^2 + 2^2 - 2(1)(2)CosB
I guess we're solving for angle B. I think we can easily reduce to -1 = CosB. So how do you solve for B? Calculator? How?
December 19, 2018, 10:01 PM
CromB is pi radians or 180 degrees
December 19, 2018, 10:01 PM
zipridersonThanks Crom.
December 19, 2018, 10:05 PM
KrankyHave you tried to look at it graphically? Represent cos(x) as a graph?
You can see that Cos(x)= -1 at -Pi or -180 degrees.
-k
December 19, 2018, 10:05 PM
Gene HillmanMy lovely wife says you can use the unit circle to find the answer or you can find the inverse cosine of -1 using your calculator.
December 20, 2018, 06:00 AM
irreverentI broke a sweat just reading the question.
December 20, 2018, 08:02 AM
snideraCos^-1 is a function on most scientific calculators, defiantly on graphing calculators.
realcalc for android is what I use anymore -no idea where my Ti89 got off to.
shft+cos is the cos^-1 button on it.
December 20, 2018, 08:03 AM
JimTheoI don't even know what button to press om my watch calculator for this.