Trigonometryhard · Past Paper
The angle of elevation of a cloud from a point h meters above a lake is α and the angle of depression of its reflection is β. The height of the cloud is:
Ah(tanβ+tanα)/(tanβ-tanα)
Bh(tanβ-tanα)/(tanβ+tanα)
Ch tanα / tanβ
Dh tanβ / tanα
✓ Correct Answer: A — h(tanβ+tanα)/(tanβ-tanα)
By equating horizontal distance from both triangles: d = (H-h)/tan α = (H+h)/tan β. H(tan β - tan α) = h(tan β + tan α).
Share this question