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EXAMPLE 16 If in a A ABC, sin A, sin B and sin C are in AP,then(a) the altitudes are in A.P. (b) the altitudes are in H.P.(c) the medians are in G.P. (d) the medians are in A.P. |
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Answer» <P>If p 1 ,p 2 ,p 3 , are the ALTITUDES from A, B, C respectively, then Δ= 2 1 ap 2 = 2 1 2 = 2 1 3
⇒p 1 = a 2Δ ,p 2 = b 2Δ ,p 3 = c 2Δ
By the law of sines sinA a = sinB b = c =k(say) ∴= ksinA 2Δ ,p 2 = ksinB 2Δ ,p 3 = ksinC 2Δ
Now, sinA,sinB,sinC are in A.P. ⇒p 1 ,p 2 ,p 3 are in H.P. |
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