Question

cos(5/13-3/5) find the exact value

Answer 1

\[\cos \left( \frac{ 5 }{ 13}-\frac{ 3 }{ 5 } \right)\]

Answer 2

help

Answer 3

well you need 2 right triangles



next use the difference expansion for cos

cos(X - Y) = cos(X)cos(Y) + sin(X)sin(Y)

find sin(X) and sin(Y) from the triangles.

hope it helps

Answer 4

so the answer is 33/65

Answer 5

nope not the correct answer...

notice how the expansion has a + sign....

Answer 6

a= 12 but + sign I don't get

Answer 7

ok... wel its the difference equation for cos

cos(A -B) = cos(A)cos(B) + sin(A)sin(B)

Answer 8

cos(a)=5/13 cos(b)=-3/5+sin(a)=12/13 sin(b)=4/5
so than it is 18/65 if not how do you work it out