Question

prove that tan65= tan 25+ 2tan40

Answer 1

Hey !


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tan65 - tan40 = tan 25 + tan 40 .

using tanA - tan B =sin(A - B)/cosAcosB and tanA + tan B
= sin( A + B)/cosAcosB


= we get :: to prove sin 25/ cos65

= sin65 / cos25 sin 25 = cos (90 - 25)

= cos 65 and sin 65

= cos (90 - 65)

= cos 25

Answer 2

tan65 - tan40 = tan 25 + tan 40 . using tanA - tan B =sin(A - B)/cosAcosB and tanA + tan B = sin( A + B)/cosAcosB we get :: to prove sin 25/ cos65 = sin65 / cos25 sin 25 = cos (90 - 25) = cos 65 and sin 65 = cos (90 - 65) = cos 25




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