Page 43 - DMTH201_Basic Mathematics-1

Basic Mathematics – I

Notes
= = q + f = L.H.S.
The result holds.

Similarly (ii) can be proved.

Property 6:

Let x = tan
Substituting in (i), (ii), (iii), and (iv) we get
–1
–1
2 tan x = 2 tan (tan ) = 2 …(i)
=

=

–1
= sin (2 sin cos )
–1
= sin (sin 2 ) = 2 …(ii)
=

=

–1
2
= cos (cos – sin )
2
= cos (cos 2 ) = 2 …(iii)
–1
=

–1
= tan (tan 2 ) = 2 …(iv)
From (i), (ii), (iii) and (iv), we get

–1
2 tan x =

Property 7

–1
(i) sin x =

=

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