WAEC - Further Mathematics (2019 - No. 34)
Find correct to the nearest degree,5 the angle between p = 12i - 5j and q = 4i +3j
59\(^o\)
60\(^o\)
75\(^o\)
76\(^o\)
توضیح
Cos \(\theta\) = \(\frac{4(12) + (-5)(3)}{\sqrt{12^2 + (-5)^2}\sqrt{4^2 + 3^2}}\)
Cos\(\theta\) = \(\frac{48 - 15}{(\sqrt{189})(\sqrt{25})}\)
\(\theta = cos^{-1}\) (\(\frac{33}{61.28}\))
\(\theta\) = cos\(^{-1}\)0.5367
\(\theta\) = 59\(^o\)