Answer:
A. I and II, only
Step-by-step explanation:
y = x
Switch variables.
x = y
y = 1/x
x = 1/y
1/x = y
y = x²
x = y²
±√x = y
y = x³
x = y³
∛x = y
h=6
cos 78⁰.
Use cos 2A = cos^2 A - sin^2 A
so cos^2 39 - sin^2 39 = cos (2*39) = cos 78.
