Mathematics for IGCSE & O level - Vectors (Section 2 - No. 42)
If a = [1, 2] and b = [-3, 1], what is the magnitude of the vector 2a + b?
√26
√10
5
√37
説明
First calculate 2a + b = 2[1, 2] + [-3, 1] = [2, 4] + [-3, 1] = [-1, 5]. Then find its magnitude √((-1)^2 + 5^2) = √26.