Question

Sin 5pi/7cos 2pi/7+sin 2pi/7 cos 5pi/7 найти значение выражения

Answer 1

$sin( \frac{5 \pi }{7}+ \frac{2 \pi }{7})=sin( \frac{7 \pi }{7})=sin \pi =0$

Answer 2

To find the value of the expression, let's use the trigonometric identity:

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

In this case, A = 5π/7 and B = 2π/7. So, we have:

sin(5π/7 + 2π/7) = sin(7π/7) = sin(π)

Now, recall that sin(π) is equal to 0. So the value of the expression is:

0