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if cot^-(-cot5x)=tan^-( cotx),0
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Asked by ajaysir635 | 26 Dec, 2023, 12:00: PM
Let cot-1 ( - cot 5x ) = tan-1 ( cot x ) = α
from LHS , cot-1 ( - cot 5x ) = α
cot( α ) = - cot(5x) ........................... (1)
Similarly from RHS
tan-1 ( cot x ) = α
tan ( α ) = cot x ..........................(2)
From eqn.(1) and (2) , we get
cot ( α ) tan (α ) = - cot(5x) cot(x) = 1
hence we get, cos(5x)cos(x) + sin(5x) sinx = 0
cos( 5x -x ) = cos(4x) = 0
cos(4x) = cos[ (2n+1) (π / 2 ) ] , where n = 0, 1, 2 ........ etc
4x = (2n+1) (π / 2 )
x = (2n+1) (π / 8 )
if n = 0 , then x = (π / 8 )
if n =1 , then x = (3 π ) / 8
Answered by Thiyagarajan K | 26 Dec, 2023, 14:26: PM
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