Math, asked by diya851, 11 months ago

cot2A×cot3A =1, find cot5A​

Answers

Answered by A1231
0

LHS = cot A . cot 2A − cot 2A . cot 3A − cot 3A . cot A

=cot A . cot 2A − cot 3A(cot 2A + cot A)

=cot A . cot 2A − cot (2A + A)(cot 2A + cot A)

=cot A . cot 2A − [cot 2A . cot A − 1cot 2A + cot A](cot 2A + cot A)

=cot A . cot 2A − cot 2A . cot A + 1

=1 =RHS


diya851: we don't have to prove it
diya851: it is given
diya851: we have to find cot5A
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