[sin(180-a) x cos(90-a) - 1]/cos(-a)
= [sin(a) x sin(a) - 1]/(-cos(a))
= [sin^2(a) -1]/(-cos(a))
= [-cos^2(a)]/(-cos(a))
= cos(a)
formula used
sin(180-a) = sin(a)
cos(90-a) = sin(a)
cos(-a) = -cos(a)
sin^2(a) + cos^2(a) = 1
all of these are easily proved by the unit circle. you might find someone to explain this. it will be very handy.
Option ( A ) is the correct answer.
Answer:
Step-by-step explanation:
1. Volume of sphere
2. Volume of hemisphere
Answer:
<em>6 1/2 inches</em>
Step-by-step explanation:
If it is 1/2 an inch per hour, and it burns for 5 hours, you will multiple to find the amount of inches burned.
5 hours x 1/2 in./hour = 2.5 inches burned in five hours
Then subtract the total burned from 9.
9 - 2.5 = 6.5
