an aircraft at an altitude of 10 000 m is flying at a constant speed on a line that will take it directly over an observer on the ground. if the observer notes that the angle of elevation o the aircraft is 60 degrees and is increasing at a rate of 1 degree per second find the speed of the plane in metres per second. i got the formula for the equation as 10 000/(Tan (a+x))=m a=angle x=seconds m=metres across. i cant think why it would be incorrect. the velocity is metres per second so delta M over Delta T or Delta y over Delta x (the gradient function) that didnt get me anywhere because i didnt know wat to sub in for the equation then i simply took an m value and a x value and used the average velocity formula but as expected it changed. plllllllllleeeassse i know the answer is staring me right in the face, im just temporaily blind. help me.