1.7.17 Linear transformations
condition: Let the fixed non-zero vectors \( a \) and \( n \) of three-dimensional space be non-orthogonal to each other. Prove the linearity of the transformation and find out its geometric meaning. \[ \varphi x=(n, x) a-(a, x) n \]
Linear transformations of matrices in the transition between bases, coordinates of vectors and linear operators.