Answer:
Identity is verified.
Step-by-step explanation:
We have to verify the identity 
To prove any identity we always prove one side(either left hand side or right hand side) of the equation equal to the other side.
In this identity we take the left hand side first
(as we know cos(a+b) = cosa×cosb-sina×sinb)
= - sinx ( Right hand side)
Hence identity is proved.
This equation uses two properties of logarithms:
So you could take the ln from left and right hand side in the equation, and get:
(2-x)ln 3 = x ln 5
then
2 ln 3 - x ln 3 - x ln 5 = 0 =>
x(ln 3 + ln 5) = 2 ln 3
so x = 2 ln 3 / (ln3 + ln5)
Now using the 1st property you can say 2 ln 3 is ln 3² = ln9
and using the 2nd property you can say ln3 + ln5 = ln15
so x= ln9 / ln15
Answer:
Euler's Formula states that:
V -E +F = 2 meaning that the vertices minus the edges plus the faces of a convex polyhedron will always equal two.
So, for the initial question, we have 40 edges and 24 faces.
So, vertices = 2 + Edges -Faces
Vertices = 2 + 40 - 24
Vertices = 18
Source: https://www.1728.org/platonic.htm
Step-by-step explanation:
