alleryFind ā · b̄ if ā = 2î + 3ĵ and b̄ = î - 2ĵ:
A2
B0
C8
D-4
Answer & Solution
Correct answer: D. -4
We have ā · b̄ = (2)(1) + (3)(-2).
That is ā · b̄ = 2 - 6.
So ā · b̄ = -4.
Keep practising Unit 9A: Parametric Equations and Plane Curves
Browse all Unit 9A: Parametric Equations and Plane Curves questions for GRE, or explore more Mathematics topics.
Related questions
The magnitude of the vector $\hat{i}+\hat{j}+\hat{k}$ is:For any vector $\vec a$, the dot product $\vec a\cdot\vec a$ equals:The value of $\hat{i}\times\hat{j}$ is:The dot product of $(2\hat{i}+3\hat{j}+\hat{k})$ and $(\hat{i}-\hat{j}+\hat{k})$ is:The unit vector in the direction of $3\hat{i} + 4\hat{j}$ is:Two non-zero vectors $\vec a$ and $\vec b$ are perpendicular if and only if:The magnitude of the cross product $|\vec{a}\times\vec{b}|$ equals:The value of $\hat{i}\cdot\hat{j}$ is: