intro practice · coding problem
Dot product and matmul shapes
Vectors a=[1,2,3], b=[4,5,6]. Compute dot(a,b). Matrices A (2×3) and B (3×2): is A·B valid? What is the output shape?
The mechanism
Three lenses keep coming back: linear algebra describes the data (vectors and matrices), calculus describes learning (gradients), probability describes uncertainty. Pick the lens that matches the question.
Expected evidence
dot=32; A·B is 2×2.
Try this drill in the practice workspace →
Hints when you need them
- Dot = sum of elementwise products.
- Inner dimensions must match for matmul.