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What is the formula for cos θ between two lines with direction ratios a1, b1, c1 and a2, b2, c2?

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Single Answer MCQ

Q-00078329

(a1a2 + b1b2 + c1c2) / (√(a1² + b1² + c1²) * √(a2² + b2² + c2²))

(a1a2 + b1b2 - c1c2) / (√(a1² + b1² + c1²) * √(a2² + b2² + c2²))

(a1b2 - a2b1) / (√(a1² + b1² + c1²) * √(a2² + b2² + c2²))

√(a1² + b1² + c1²) / √(a2² + b2² + c2²)

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