sin (90°- A) cos (90°- A)=
tan A
1+tan? A
Answers
Answered by
0
Answer:
It's a generic right triangle, with a
90
o
angle as indicated by the little box and an acute angle
a
. We know the angles in a right triangle, and a triangle in general, must add to
180
o
, so if we have an angle of
90
and an angle of
a
, our other angle must be
90
−
a
:
(
a
)
+
(
90
−
a
)
+
(
90
)
=
180
180
=
180
Answered by
2
Step-by-step explanation:
LHS = sin(90 - A ) * cos ( 90 - A )
= CosA sinA ----( 1 )
RHS = tanA / ( 1 + tan² A )
= tan A / sec² A
= ( SinA/cosA ) / ( 1/ cos² A )
= ( SinA cos² A ) / cosA
= SinAcosA ----( 2 )
From ( 1 ) and ( 2 ) ,
LHS = RHS
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