T = k/R where k is the constant of variation, T=time and R=speed.
Plug in the given values:-
12 = k/60
k = 12*60 = 720
So the equation of variation is T = 720/R
At 85 mph we have
T = 720 / 85 = 8.47 hours (answer)
No, there is no 'greatest integer'. That is because positive numbers can go up tp infinite, and we do not know where numbers stop.
However, there is a negative greatest integer because the ones that's closes to zero is -1.
128, -512, 2048
Multiply by -4 to get each new term
The answer is C 8/2=4 and 74/2=37
Seca(1-sina)(seca+tana)=1
Left hand side
=(1-sina) (seca +tana) / cosa
=seca +tana - sinaseca - sinatan / cosa
=seca + tana -tana -(sin^2a/cosa) / cosa
=(1/cosa - sin^2a/cosa) / cosa
= (1-sin^2a / cosa) / cosa
= (1-sin^2a)/ (cos^2a)
=1 (verified)