Một dao động điều hoà theo phương trình :x=cos(10πt+π/4)(cm) Vsof thời điểm t=0 vật đang ở đâu và di chuyển theo chiều nào?vận tốc bằng bao nhiêu?

Sawyer is studying diffraction. he draws a diagram of a plane wave to show how light waves travel. which best describes sawyer’s error? the wave fronts should be perpendicular to the direction in which the waves move. the arrow showing the direction of movement of the waves should be pointing to the left. the arrow showing the direction of movement of the waves should be pointing downward. the wave fronts should be both parallel and perpendicular to the direction in which the waves move.