12. (10%) Let f1 =x+a and f2 = x-a , , be two vectors in the vector space C[0, 1] with inner
product <f,8>:=.
【題組】(b) (6%) Now set a = 1. Find functions g1and g2 such that {g1, g2} is an orthonormal set that satisfies
Span(g1) = Span(f1) and Span(g1,g2) =Span(f1, f2).