Question

24) IF LA, LB and LC are the angles of a triangle, prove that cosec
(LA+ LB
sec
2
2.​

Answer 1

Answer

Given A, B, C are the interior angles of ∆ABC

= A + B + C = 180°

=A + B = 180°- C

LHS = cosec (A+B)

2

= cosec (180°- C)

2

=cosec ( 90°- C )

2

=sec C

2

=RHS

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