One of the most important and conceptual question from trigonometry in which we have to find the speed of an aeroplane when the angle of elevation of an aeroplane from a point on the ground is 45 degree. After 15 seconds of flight the angle changes to 30 degree.If the plane is flying at a constant height of 2500 m.
RS Aggarwal, Class 10, chapter 14, question no 25.
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