I only have one attempt left and it doesn't say which is right or wrong. Please help. Thank you!

(1 point) Are the following statements true or false? True 1. If y = 11 + 22 , where 7.1 is in a subspace W and 5:2 is in Wi , then 21 must be the orthogonal projection of y onto W. False 2. If W is a subspace of IR\" and if v is in both W and Wi , then v must be the zero vector. True 3. Let 111, 112, ,un be an orthonormal basis of a vector space V. In the Orthogonal Decomposition Theorem, each term p = (b, 111 )111 + + (b, 11,.t )1!\" is itself an orthogonal projection of b onto a subspace of V. False 4. If an n X 1) matrix U has orthonormal columns, then UUTX = X for all X in IR" . True 5. The best approximation to y by elements of a subspace W is given by the vector y proj W(y). Note: In order to get credit for this problem all answers must be correct