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4
Equation with cosinus
Equation with cosinus
Source:
October 28, 2017
geometry
algebra
Trigonometric Equations
Problem Statement
Given triangle
A
B
C
ABC
A
BC
such that angles
A
A
A
,
B
B
B
,
C
C
C
satisfy
cos
A
20
+
cos
B
21
+
cos
C
29
=
29
420
\frac{\cos A}{20}+\frac{\cos B}{21}+\frac{\cos C}{29}=\frac{29}{420}
20
cos
A
+
21
cos
B
+
29
cos
C
=
420
29
Prove that
A
B
C
ABC
A
BC
is right angled triangle
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