cosine rule

[Captain Trips]

i'm bad enough at trigonometry without having to code it cosine rule is: b2=a2+c2- 2bccosA so: cosB=a2+c2-b2/2ac B=cos^-1(cosB) I'm having problems coding the last line,'cos^-1',any help appreciated

[Stefan Troschuetz]

I guess the follwoing is demanded:

B = Math.Acos(cosB);

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[Captain Trips]

my code looks like this,'A' should come out at about 70 degrees double sideA=6.75; double sideB=4.5; double sideC=6.7; double cosA=(Math.Pow(sideB,2) + Math.Pow(sideC,2) - Math.Pow(sideA,2)) / (2 * sideB * sideC); tried double A=Math.Acos(cosA);

[Stefan Troschuetz]

And it does, if you pay attention to the information the documentation gives you. In this case you have to multiply the return value of Math.Acos by 180/Math.PI to convert it from radians to degrees.

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