a · b = a₁b₁ + a₂b₂ + a₃b₃

Vectors Calculator

Calculate vector operations with step-by-step solutions. Supports 2D and 3D vectors for GCSE and A-Level.

Step-by-step learning with explanations

Vectors Calculator

Enter Vector Details

Vector a

2D

Vector b

2D
Interactive Visualization
xy-6-6-5-5-4-4-3-3-2-2-1-1112233445566abbaa+b

Enter vector values and click Calculate to view the result and geometric interpretation.

To add vectors, you add their corresponding components.

Adding Magnitudes

Remember that . You must add the vectors first, then find the magnitude.

Example

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Understanding Vectors

What is a Vector?

A vector is a quantity with both magnitude (size) and direction. Written as column vectors or coordinate pairs like (3, 4) or (1, 2, 5).

Examples:

Displacement, velocity, force, acceleration

Vectors vs Scalars

  • Vectors:Have magnitude AND direction (e.g., velocity)
  • Scalars:Have magnitude only (e.g., speed, temperature)
  • The dot product of vectors gives a scalar
  • The cross product of vectors gives a vector

Key Vector Operations

Addition & Subtraction

Add or subtract corresponding components.

(3, 4) + (1, 2) = (4, 6)

3+1=4, 4+2=6

(5, 8) - (2, 3) = (3, 5)

5-2=3, 8-3=5

Dot Product (Scalar Product)

Multiply corresponding components and add. Result is a scalar.

a · b = a₁b₁ + a₂b₂ + a₃b₃

(3, 4) · (1, 2) = 3×1 + 4×2 = 3 + 8 = 11

💡 If a · b = 0, vectors are perpendicular!

Cross Product (3D Only)

Produces a vector perpendicular to both inputs. Order matters!

a × b = (a₂b₃ - a₃b₂, a₃b₁ - a₁b₃, a₁b₂ - a₂b₁)

(1, 0, 0) × (0, 1, 0) = (0, 0, 1)

⚠️ a × b ≠ b × a (not commutative!)

Magnitude (Length)

Use Pythagoras in multiple dimensions.

2D:

|v| = √(x² + y²)

3D:

|v| = √(x² + y² + z²)

Exam Tips

Perpendicular Check

If a · b = 0, vectors are perpendicular. This is a common exam question!

Parallel Check

Vectors are parallel if one is a scalar multiple of the other: a = kb.

📐

Unit Vectors

Always simplify to unit vectors when asked. Divide by magnitude.

🔄

Cross Product Order

Remember: a × b = -(b × a). Order matters for cross products!

📍

Position Vectors

AB = b - a (end minus start). Common mistake is subtracting wrong way.

Exact Form

Leave answers as surds (√5) unless told to give decimals.

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