Prove mathematically the logic used in if the boat is taken along the direction perpendicular to the direction of river - Physics - Motion In A Straight Line

Question

Prove mathematically the logic used in if the boat is taken along
the direction perpendicular to the direction of river flow the
river can be crossed in the shortest time

Shivam Ranjan Sinha · Accepted Answer

Prove mathematically the logic used in if the boat is taken along the direction perpendicular to the direction of river flow the river can be crossed in the shortest time.