Question

Resolva as equações em C.

a) x^2 + 81= 0

b) x^2 - 4x + 5 =0

c) - x^2 - 2x -2 = 0

d) x^2+ 3= 0

Answer 1

Resposta:

a) x² + 81 = 0

x² = -81

x = +-√-81

x = +-√[9² * (-1)]

x = +-9√-1

x = +-9i

b) Δ = b² - 4ac = (-4)² - 4*1*5 = -4

x1 = (-b + √Δ) / 2a = (4 + √-4) / 2 = (4 + 2i) / 2 = 2 + i

x2 = (-b - √Δ) / 2a = (4 - √-4) / 2 = (4 - 2i) / 2 = 2 - i

c) Δ = b² - 4ac = (-2)² - 4*(-1)*(-2) = -4

x1 = (-b + √Δ) / 2a = (2 + √-4) / (-2) = (2 + 2i) / (-2) = -1 - i

x2 = (-b - √Δ) / 2a = (2 - √-4) / (-2) = (2 - 2i) / (-2) = -1 + i

d) x² + 3 = 0

x² = -3

x = +- √-3

x = +- √3 * √-1

x = +- √3i