Fermi
·
Concept Library
·
Courses
·
Books
·
Problems
·
Simulations
·
Math Wiki
·
High School
Fermi
›
Problems
Mathematics
Mathematics
Problem
Simplify
cos
13
∘
cos
17
∘
−
sin
13
∘
sin
17
∘
\cos 13^{\circ}\cos 17^{\circ}-\sin 13^{\circ}\sin 17^{\circ}
cos
1
3
∘
cos
1
7
∘
−
sin
1
3
∘
sin
1
7
∘
. a)
2
2
\dfrac{\sqrt{2}}{2}
2
2
b)
−
3
2
-\dfrac{\sqrt{3}}{2}
−
2
3
c)
3
2
\dfrac{\sqrt{3}}{2}
2
3
d)
1
2
\dfrac{1}{2}
2
1
Browse the problem library