NCERT Class 12 · Ch 10 Miscellaneous Exercise · Q1
NCERT Class 12 Maths · Chapter 10 Vector Algebra · Miscellaneous Exercise Question 1
Write a unit vector in the XY-plane making 30° with positive x.
💡 Concept Hints
- Write the vector components and identify the required direction or geometric relation.
- Use the magnitude, dot-product, cross-product or section formula that matches the requested quantity.
✅ Step-by-Step Solution
Final Answer: (√3/2)i+(1/2)j; reflected alternative (√3/2)i−(1/2)j also makes 30° with +x.
- A planar unit vector at oriented angle α is cos α i+sin α j.
- For counterclockwise α=π/6 this gives (√3/2,1/2,0). If only the unsigned angle to +x is specified, the negative-y reflection is also valid.
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