Answer:
see explanation
Step-by-step explanation:
Using the double angle identity for sine
sin2x = 2sinxcosx
Consider left side
cos20°cos40°cos80°
= (2sin20°cos20°)cos40°cos80°
= (2sin40°cos40°)cos80°
= (sin80°cos80° )
= (2sin80°cos80° )
= . sin160°
= . sin(180 - 20)°
= . sin20°
= = right side , thus proven
9514 1404 393
Answer:
-3, 7, 8
Step-by-step explanation:
You can fill in the boxes from the table values as shown in the attachment.
The leading coefficient is negative because the parabola opens downward. The value of it is the change in y-value as x changes by 1 unit either side of the vertex.
The vertex is identified by the fact that the y-values are symmetrical either side of the vertex.
