Margliður – Æfing 1 – Svör

1) f(x) + g(x) = 2x3 – x2 – 41x + 57

f(x) – g(x) = 2x3 – x2 – 45x + 63

f(x)·g(x) = 4x4 – 8x3 – 83x2 + 9x – 180

f(x)/g(x) = x2 + x – 20

2) f(x) + g(x) = 9x2 + 1 + 9x2 – 1 = 18x2

f(x) – g(x) = 9x2 + 1 – 9x2 + 1 = 2

f(x)·g(x) = (9x2 + 1)(9x2 – 1) = 81 x2 – 1

f(x)/g(x) = 1 + 2/(9x2 – 1)

3) f(x) + g(x) = 2x3+ 2x2–2x

f(x) – g(x) = x- 2x2 – 2x + 2

f(x)·g(x) = x6 + 2x5 – 2x4 – 6x3 + 2x + 1

f(x)/g(x) = 1 – 2/(x+1)