<span>a. True
The question is pretty much the entire definition of a radian. For an unit circle, its entire circumference is 2π and the entire circle has 2π radians. A quarter circle, or 90°, or π/2 radians, have 1/4th of the circumference. And 2π/4 is π/2. This natural relationship is WHY higher mathematics uses radians for the measurement of angles rather than arbitrary units such as degrees.</span>
Answer:
-16
Step-by-step explanation:
-k² -(3k-5n)+4n k=-1 , n= -2
= -(-1)² - ( 3(-1) -5(-2) )+4(-2)
= -1-(-3+10)-8
= -1-(7)-8
= -1-7-8
= -16
Let ‘s’ be the son’s age 12 years ago.
Let ‘f’ be the father’s current age.
4 years ago, the son was:
s-4
So, his father is currently:
3(s-4)
=
3s-12
Therefore:
f = 3s-12
In twelve years, the son will be:
s+12
And the father will be:
f+12
This can also be written as:
3s-12+12 as the fathers younger age would be f = 3s+12
=
3s
So, we know that s+12 is half the fathers current age, meaning the father is currently 2(s+12) which is equivalent to 2s+24. Also, we know that the father is currently 3 times the sons age 12 years ago, so 3s (proven by the calculations we made above). Therefore, 2s+24=3s which means 24=s. We can then substitute this, and we will receive 24+12 = 36
Son’s current age: 36
We then substitute the son’s age 12 years ago into 2s+24 to give us the father’s age.
2(24)+24 = 72
Father’s current age: 72
Joseph can buy 12 comic books with $32.40.
