Răspuns:
Explicație pas cu pas:
a = (1/√3 + 2/√12 + 3/√27 + 4/√48) : 2/3
= (1/√3 + 2/2√3 + 3/3√3 + 4/4√3) : 2/3
= (1/√3 + 1/√3 + 1/√3 + 1/√3) : 2/3 = 4/√3 : 2/3 = 4/√3 * 3/2 = 2*3/√3
= 2*3√3/3 = 2√3
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26^2 - 10^2 = 676 - 100 = 576 = 24^2
20^2 - 16^2 = 400 - 256 = 144 = 12^2
b = 24/12*3√2/2 = 2*3√2/2 = 3√2
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a + b = 2√3 + 3√2
Ia - bI = I2√3 - 3√2I = 3√2 - 2√3
(a + b)*Ia - bI = (3√2 + 2√3)(3√2 - 2√3) = 18 - 12 = 6
