A man on the top of a vertical observation tower observes a car moving at a uniform speed coming directly towards it. If it takes 12 minutes for the angle of depression to change from 30 degrees to 45 degrees , how long will the car take to reach the observation tower from this point? ,
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Step-by-step explanation:
Let Let the uniform speed be x
Time taken by car to move distance x = 12 so
Distance travelled by car = speed ×time =12x
Let distance to reach foot of tower be y
Use tan 30 = p/b
1/√3= p/12x+y
12x+y/√3=p
Now for small triangle
Use tan 45 = p/b
1=p/y
P=y
Compare both values of p now
12x+y /√3=y
Y(1-√3)/-12=x
Hence found
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