1.In a triangle ABCABCABC, the sides ABABAB and ACACAC are represented by the vectors 3i^+j^+k^3\hat{i}+\hat{j}+\hat{k}3i^+j^+k^ and i^+2j^+k^\hat{i}+2\hat{j}+\hat{k}i^+2j^+k^, respectively. Calculate the angle ABCABCABC.a.cos−1(555)\cos^{-1}\left(\dfrac{5}{\sqrt{55}}\right)cos−1(555)b.cos−1(111)\cos^{-1}\left(\dfrac{1}{\sqrt{11}}\right)cos−1(111)c.90∘90^\circ90∘d.180∘−cos−1(511)180^\circ - \cos^{-1}\left(\dfrac{5}{11}\right)180∘−cos−1(115)Login to continueOnly logged in users canattempt or see the solution.
