+1124 Hi friends,
trust you are all doing well...please just quick guidance with this problem?
If Sin22 = k, use a diagram to determine Cos158 in terms of k
My problem is that if the angle is given a \(\theta \) for example, I can do the sum, I'm just not sure how to work with a given angle?..Thank you very much indeed!
+33661 cos(158) = cos(180 - 22) = cos(180)*cos(22) + sin(180)*sin(22) = -cos(22) = -√(1-sin(22)^2) = - √(1 - k^2)
+1124 Hi Alan,
Yes, I worked on it and kinda got it right, thank you klindly, however, maybe just one that I do not see how to go about is to calculate Sin11?...Must I devide Sin22 by 2 and then proceed, in which case I'm not sure how to?..or is it an entirely different approach?..please if you don't mind..
+33661 Note that cos(22) = √(1 - k^2) from the previous result.
Also cos(22) = cos(11 + 11) = 1 - 2*sin(11)^2
Can you take it from there?
+1124 Hi Alan,
I see, so I then say
\(Cos22=Cos2(11)\)
\(Cos22=1-2Sin^211\)
\(\sqrt{1-k^2}=1-2Sin^211\)
\(2Sin^211=1-\sqrt{1-k^2}\)
\(Sin11=\sqrt{1-\sqrt{1-k^2} \over2}\)
I think this might be it?
