How to find the orthogonal projection of a vector [b]y[/b] onto a subspace W? [br]A popular method is to use an orthogonal basis in W. [br]Then, the output is the sum of the orthogonal projections of [b]y[/b] onto the coordinate axes. [br][br]This applet also illustrates the formula for the Fourier coefficients, see the projections of [b]y[/b] on the coordinate axes. [br][br]Remark: This is a modified version of the applet https://www.geogebra.org/m/zxxfqa4t by Trefor Bazett[br]