Chemegate

GATE 2025 Chemical Engineering, Q12 · Mathematics

The correct answer is B, 1.

Question

Consider a Cartesian coordinate system defined over a 3-dimensional vector space with orthogonal unit basis vectors î, ĵ and k̂. Let vector u =2= \sqrt{2} î +(1/2)+ (1/\sqrt{2}) ĵ + k̂, and vector v =(1/2)= (1/\sqrt{2}) î +2+ \sqrt{2} ĵ k̂. The inner product of these vectors (u·v) is:

  • A. 0
  • B. 1
  • C. −1
  • D. 2

Official answer: 1

Why

GATE 2025 official key: (B). The dot product is the sum of componentwise products: u·v =(2)(1/2)+(1/2)(2)+(1)(1)=1+11=1.= (\sqrt{2})(1/\sqrt{2}) + (1/\sqrt{2})(\sqrt{2}) + (1)(−1) = 1 + 1 − 1 = 1.

Explanation cross-checked for consistency. Final answer matches the official IIT answer key.