MathematicsHard249×since 2002Q2596A vector a⃗\vec{a}a is parallel to the line of intersection of the plane determined by the vectors i^,i^+j^\hat{i}, \hat{i}+\hat{j}i^,i^+j^ and the plane determined by the vectors i^−j^,i^+k^\hat{i}-\hat{j}, \hat{i}+\hat{k}i^−j^,i^+k^. The obtuse angle between a⃗\vec{a}a and the vector b⃗=i^−2j^+2k^\vec{b}=\hat{i}-2 \hat{j}+2 \hat{k}b=i^−2j^+2k^ is :A3π4\frac{3 \pi}{4}43πB2π3\frac{2 \pi}{3}32πC4π5\frac{4 \pi}{5}54πD5π6\frac{5 \pi}{6}65πCheck answerSkip