a + 2b = (5;-1;2) + 2*(3;2;-4a + 2b = (5;-1;2) + (6;4;-8a + 2b = (11;3;-6)
|a + 2b| = √(11^2 + 3^2 + (-6)^2|a + 2b| = √(121 + 9 + 36|a + 2b| = √166
|a + 2b| ≈ 12.8848942
Итак, |a + 2b| ≈ 12.8848942
a + 2b = (5;-1;2) + 2*(3;2;-4
a + 2b = (5;-1;2) + (6;4;-8
a + 2b = (11;3;-6)
|a + 2b| = √(11^2 + 3^2 + (-6)^2
|a + 2b| = √(121 + 9 + 36
|a + 2b| = √166
|a + 2b| ≈ 12.8848942
Итак, |a + 2b| ≈ 12.8848942