Question

Please help and show working (please)

Answer 1

In mathematical notation, ∑ means summation. So wherever you see the symbol, you have to sum over all elements in the set. Let's solve the question.

a. ∑m means, to sum all elements in the set m: ∑m = 12 + 15 + 20 + 30 = 77

b. ∑$f^{2}$ means to sum all elements in the set f as the square of the elements f = $5^{2} + 9^{2} + 10^{2} + 16^{2} = 25 + 81 + 100 + 256 = 462$

c. ∑mf means to sum all elements as the product of the elements of m and f = (12×5) + (15×9) + (20$(12^{2}(5)) + (15^{2}(9)) + (20^{2}(10)) + (30^{2}(16)) = 21145$10) + (30×16) = 875

d. ∑$m^{2}f$ means to sum all elements as the product of the square of m and f = $((12*12)(5)) + ((15*15)(9)) + ((20*20)(10)) + ((30*30)(16)) = 21145$