Angle A ~ Angle FEC
Angle B ~ Angle EFC
Angle BDA ~ Angle FCE
AB ~ EF
BD ~ FC
AD ~ EC
Answer:
We have to prove
sin(α+β)-sin(α-β)=2 cos α sin β
We will take the left hand side to prove it equal to right hand side
So,
=sin(α+β)-sin(α-β) Eqn 1
We will use the following identities:
sin(α+β)=sin α cos β+cos α sin β
and
sin(α-β)=sin α cos β-cos α sin β
Putting the identities in eqn 1
=sin(α+β)-sin(α-β)
=[ sin α cos β+cos α sin β ]-[sin α cos β-cos α sin β ]
=sin α cos β+cos α sin β- sinα cos β+cos α sin β
sinα cosβ will be cancelled.
=cos α sin β+ cos α sin β
=2 cos α sin β
Hence,
sin(α+β)-sin(α-β)=2 cos α sin β
Step-by-step explanation:
(2 cos(2x)) / (cot x – tan x)
Multiply top and bottom by sin x cos x:
(2 cos(2x) sin x cos x) / (cos² x – sin² x)
Use double angle formula:
(2 cos(2x) sin x cos x) / (cos(2x))
2 sin x cos x
Use double angle formula:
sin(2x)
Answer:
$1036
Step-by-step explanation:
His room is 8 x 9 = 72 feet. The cost of each square foot is $14.
So 72ft x $14 = $1036. So its going to cost him $1036.
i hope i helped :)
