MathematicsMedium202×since 2002Q5826Let a→=αi^+j^−k^\overrightarrow{\mathrm{a}}=\alpha \hat{i}+\hat{j}-\hat{k}a=αi^+j^−k^ and b→=2i^+j^−αk^,α>0\overrightarrow{\mathrm{b}}=2 \hat{i}+\hat{j}-\alpha \hat{k}, \alpha>0b=2i^+j^−αk^,α>0. If the projection of a→×b→\overrightarrow{\mathrm{a}} \times \overrightarrow{\mathrm{b}}a×b on the vector −i^+2j^−2k^-\hat{i}+2 \hat{j}-2 \hat{k}−i^+2j^−2k^ is 30, then α\alphaα is equal to :A152\frac{15}{2}215B8C132\frac{13}{2}213D7Check answerSkip