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The projection of the vector `vec(A)= hat(i)-2hat(j)+hat(k)` on the vector `vec(B)= 4hat(i)-4hat(j)+7hat(k)` isA. `(19)/9`B. `(38)/9`C. `8/9`D. `4/9` |
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Answer» Correct Answer - A Here, `vec(A)= hat(i)-2hat(j)+hat(k)` `vec(B)= 4hat(i)-4hat(j)+7hat(k)` The projection of `vec(A)` on `vec(B)= A cos theta` `A cos theta= (AB cos theta)/B= (vec(A).vec(B))/B` `=((hat(i)-2hat(j)+hat(k)).(4hat(i)-4hat(j)+7hat(k)))/(sqrt((4)^(2)+(-4)^(2)+(7)^(2)))` `=(4+8+7)/(sqrt(18))=(19)/9` |
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