How do you find the projection of u=<4,8> onto v=<-1,2>? Precalculus Dot Product of Vectors Vector Projection 1 Answer VinÃcius Ferraz May 28, 2017 (-12/5, 24/5) Explanation: u * v = ||u|| * ||v|| * cos theta But you want ||u|| * cos theta * hat v = frac{u * v}{||v||} * frac{v}{||v||} = frac{u*v}{v*v}*v = frac{4(-1) + 8*2}{(-1)^2 + 2^2} * (-1, 2) = frac{12}{5} * (-1, 2) Answer link Related questions What is the vector projection formula? What are vector projections used for? How does a vector differ from its projection? How do I find the orthogonal vector projection of vec{a} onto vec{b}? How do I determine the vector projection of a vector? What is vector projection? How do I find the orthogonal projection of a vector? How do I find the orthogonal projection of two vectors? How do you find the vector C that is perpendicular to A-> -3x+9y-z=0 and which vector C... Question #8f5e6 See all questions in Vector Projection Impact of this question 2316 views around the world You can reuse this answer Creative Commons License