Direction Of Resultant Vector Formula — the NEET Physics formula with its derivation, variables, validity constraints and worked solver.
Direction of Resultant Vector Formula Calculates the direction of the resultant vector when adding two vectors using the parallelogram law. Applies to any vector quantity (velocity, force, acceleration). Construct a parallelogram with sides A and B and angle theta between them. Extend the line of vector A and drop a perpendicular from the tip of B to this extension. The perpendicular component is B sin(theta). The parallel component added to A is B cos(theta). Apply trigonometry to the right-angled triangle formed: tan(alpha) = Opposite/Adjacent = (B sin(theta)) / (A + B cos(theta)). Vector magnitudes A and B must be non-negative. The denominator (A + B cos theta) must not be zero to compute tan(alpha) directly (singularity at 90 degrees relative to resultant, i.e., vertical). Confusing alpha (angle with vector A) with the angle with vector B. Using degrees directly in computational functions instead of radians. Assuming the resultant angle bisects the vectors (only true if magnitudes A and B are equal).