Answer:
1. 15 - 5n where n>=1
2. n² where n>=1
Step-by-step explanation:
1. {10, 5, 0, -5, -10} is an Arithmetic Progression
nth term is a + (n - 1)d
where a = first term, n= nth term, d= common difference.
a = 10, d = -5 (5-10, 0-5, -5-0, -10-(-5))
Therefore, nth(General) term of the sequence:
= 10 + (n - 1)-5
= 10 + (-5n) + 5
= 10 + 5 - 5n
= 15 - 5n
Test:
if n = 1; 15 - 5(1) = 10
if n = 2; 15 - 5(2) = 5
if n = 3; 15 - 5(3) = 0 and so on.
2. {1, 4, 9, 16, 25}
The general term of the sequence is n²
Test:
if n = 1; 1² = 1
if n = 2; 2² = 4
if n = 3; 3² = 9 and so on.
We can see that revolving the region formed by intersecting 3 lines, we will get 2 cones that are connected their bases.
Volume of the cone V=1/3 *πr²*h
1) small cone has r=5, and h=5
Volume small cone V1= 1/3 *π*5²*5 = 5³/3 *π
2) large cone has r=5, and h=21-6=15, h=15
Volume large cone V2= 1/3 *π*5²*15 = 5³*π
3) whole volume
5³/3 *π + 5³*π=5³π(1/3+1)=((5³*4)/3)π=(500/3)π≈166.7π≈523.6
Area
we see 2 right triangles,
Area of the triangle=1/2*b*h, where b -base, h -height
1) small one, b=5, h=5
A1=(1/2)*5*5=25/2
2)large one, b=5, h=15
A2=(1/2)*5*15=75/2
3)
whole area=A1+A2=25/2+75/2=100/2=
50
3*-3^2+5*-3-14
3*-9+(-15)-14
-27+-15-14
-42-14
-56
Answer:
(5,9)
Step-by-step explanation:
3y=4x+7
5y=4x+25
Subtract the two equations to eliminate x
5y=4x+25
-( 3y=4x+7)
------------------
2y = 0x +18
Divide by 2
2y/2 = 18/2
y =9
Now find x
3y = 4x+7
3*9 = 4x+7
27 = 4x+7
Subtract 7
20 = 4x
Divide 4
20/4 = 4x/4
5 =x
(5,9)