MathDB
Problems
Contests
National and Regional Contests
China Contests
National High School Mathematics League
1983 National High School Mathematics League
9
Fill In the Blank(EASY!)
Fill In the Blank(EASY!)
Source: 1983 National High School Mathematics League, Exam One, Problem 9
February 21, 2020
trigonometry
Problem Statement
In
△
A
B
C
,
sin
A
=
3
5
,
cos
B
=
5
13
\triangle ABC,\sin A=\frac{3}{5},\cos B=\frac{5}{13}
△
A
BC
,
sin
A
=
5
3
,
cos
B
=
13
5
, then
cos
C
=
\cos C=
cos
C
=
________.
Back to Problems
View on AoPS