linear algebra
posted by Anonymous .
Solve for x if the vectors (2, x, 7x) and (x, 3, 2) are orthogonal

if orthogonal, then their dot product is zero
(2,x,7x) . (x , 3, 2) = 0
2x + 3x  14 + 2x = 0
7x = 14
x = 2
check:
(2,2,5).(2,3,2) = 4 + 6  10 = 0
Respond to this Question
Similar Questions

math
Find an orthonormal basis for the subspace of R^3 consisting of all vectors(a, b, c) such that a+b+c = 0. The subspace is twodimensional, so you can solve the problem by finding one vector that satisfies the equation and then by constructing … 
Linear Algebra
Hello ! i try to solve Linear algebra 2 questions(but need them be written properly as mathmatical proofs) Having A matrice nXn: 1)proove that if A^2=0 the columns of matrice A are vectors in solution space of the system Ax=0 (x and … 
Math  Vectors
Prove that vector i,j and k are mutually orthogonal using the dot product. What is actually meant by mutually orthogonal? 
Linear Algebra, orthogonal
The vector v lies in the subspace of R^3 and is spanned by the set B = {u1, u2}. Making use of the fact that the set B is orthogonal, express v in terms of B where, v = 1 2 13 B = 1 1 2 , 1 3 1 v is a matrix and B is a set of 2 … 
Math
Mark each of the following True or False. ___ a. All vectors in an orthogonal basis have length 1. ___ b. A square matrix is orthogonal if its column vectors are orthogonal. ___ c. If A^T is orthogonal, then A is orthogonal. ___ d. … 
math
given that vectors(p+2q) and (5p4q) are orthogonal,if vectors p and q are the unit vectors,find the product of vectors p and q? 
math
given that vectors(p+2q) and (5p4q) are orthogonal,if vectors p and q are the unit vectors,find the dot product of vectors p and q? 
linear algebra urgent
For the orthogonal matrix A = 1/sqrt(2) 1/sqrt(2) 1/(sqrt(2)) 1/sqrt(2) verify that (Ax,Ay)=(x,y) for any vectors x and y in R2. Can someone please explain this 
linear algebra
Hello, how can I proof the next theorem? I have a linear transformation T(X) that can be express as T(X)=AX and A is an orthogonal matrix, then T (X)=X , I was doing this: T (X)=sqrt(<AX,AX>) But I don't know what 
Linear Algebra
Hi, I really need help with these True/False questions: (a) If three vectors in R^3 are orthonormal then they form a basis in R^3. (b) If Q is square orthogonal matrix such that Q^2018 = I then Q^2017 = Q^T. (c) If B is square orthogonal …