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In an acute angled triangle which one of...

In an acute angled triangle which one of the following is true :
(i) `(a sec A + b sec B + c sec C)/(tan A. tan B. tan C) = 2R`
(ii) `(cos A)/(sqrt(4 R^(2) - a^(2))) = (cos B)/(sqrt(4R^(2) - b^(2))) = (cos C)/(sqrt(4R^(2) - c^(2)))`
(iii) `b^(2) = a^(2) cos^(2) C + c^(2) cos^(2) A + 2a c cos A. cos C`
(iv) `r cot.(A)/(2) + a = r cot.(B)/(2) + b = r cot.(C )/(2) + c`

A

(i), (ii)

B

(ii), (iii)

C

(i), (ii), (iii)

D

(i), (ii), (iii), (iv)

Text Solution

Verified by Experts

The correct Answer is:
D
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