Trigonometryhard · Past Paper
The angle of elevation of a stationary helicopter from a point is 60°. After rising 100 m vertically, the angle of depression of the point is 45°. Find the original height.
A50(√3+1) m
B100(√3+1) m
C100 / (√3-1) m
D200 m
✓ Correct Answer: A — 50(√3+1) m
Initial: h/d = tan 60. Final: (h+100)/d = tan (90-45)=1? No, depression is from top. (h+100)/d = tan 45? No, angle with horizontal. (h+100)/d = cot 45. Solving gives h = 100 / (√3 - 1) = 50(√3+1).
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