Answer:
Triangles ABC and DEF have the following characteristics :B and E are right angles A=D, BC=EF which congruence theorem can be used to prove ABC =DEF
Derivitive of cosx=-sinx
dy/dx sinx=cosx
and use chain rue
2cosx=-2sinx
2cos2x=-4sin2x
so
-2sinx-4sin2x id the deritivitve
Answer:
<h2>This triangle is a right triangle:</h2><h2>36² + 15² = 39².</h2>
Step-by-step explanation:
If a ≤ b <c is the length of the sides of a right triangle, then:

We have

Check the equality:



It's a right triangle.