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Mathematics
Mathematics
Problem
In
△
D
E
F
\triangle DEF
△
D
E
F
, angle
F
F
F
is a right angle. The hypotenuse is
D
E
=
25
cm
DE = 25\,\text{cm}
D
E
=
25
cm
and one of the perpendicular sides is
E
F
=
7
cm
.
EF = 7\,\text{cm}.
E
F
=
7
cm
.
a. (i) Determine the length of the third side
D
F
DF
D
F
. b. (ii) Find
sin
E
\sin E
sin
E
,
cos
E
\cos E
cos
E
and
tan
E
\tan E
tan
E
. c. (iii) Show that
sin
2
E
+
cos
2
E
=
1
\sin^2 E + \cos^2 E = 1
sin
2
E
+
cos
2
E
=
1
for this triangle.
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