Remaining Time: 11:34:48 The sigma notation for the sum is a standard notation in mathematics used to concisely express sums with a great number of terms. See your textbook for more information. Associate the equivalent expressions: -ELIf(21) -Er of (x; ) 1. f(zo) + f(21 ) + f(12) + .". + f(in) 2. nf (x1) 3. TO + 1 + 12 + x3 + . . . + in 4. f(x1 ) + f(12 ) + ... + f (in)