Please help with 2 Geometry Problems for a study guide for a pre-test on Monday. Thanks?

Question

Question 1
 (−3ˏ21)ˏ  (−2ˏ12)ˏ  (−1ˏ5)ˏ  (0ˏ0)ˏ  (1ˏ−3)ˏ  (2ˏ−4)ˏ  (3ˏ−3)

A) Identify which type of function is represented in the table.
Quadratic, Linear, Exponential, Neither

B) Is the function:
 a)Increasing over {-3, 2]
 b)decreasing over [-3, 2]
 c)always Increasing
 d)always decreasing

Question 2
An object is launched from certain height into the air. The height is modeled by the the function h(t) = -4.8t^2+23t+20. The time (t) is measured in seconds.

A) What is the maximum height?
B) After how many seconds will it hit the ground?
C) From what height (initial height) was the object launched?
D) determine the domain for the above scenario?

Anonymous · Answer

A) y = (x^2) - 4x; I shall let you guess

B) use calculus as dy/dx = 2x - 4; set it to zero; 0 = 2x - 4; x = 2
This means use a number between a < 2 < a

Due to you multiply choice answer it is recommend as make a = 1 as y(1) = -3 as given therefore 
decreasing over [-3, 2]

2.A) What is the maximum height? Use calculus 
h(t) = -4.8t^2+23t+20
dH/dt = 23 - 9.6t; set it 0 = 23 - 9.6t; t = 115/48
Re-plug into the function as 
h(115/48) = -4.8t^2+23t+20; h(115/48) = 4565/96 units as max height

2B) After how many seconds will it hit the ground? 
set the -4.8t^2+23t+20 = 0 as t = (5/48)*(23 + sqrt(913))

2C) From what height (initial height) was the object launched? 
make t = 0 as it shall make h(t) = 20 units

2D) The domain is all real numbers

Lilly J · Answer

Meant to comment

Looking at your work, for Question 2. I get the below answer for A & B.  Are they correct? Thanks
 A) I have the maximum height 47.55 or 47.6
 B) I have 5.5 seconds that it will hit the ground

Trending News

Please help with 2 Geometry Problems for a study guide for a pre-test on Monday. Thanks?

2 Answers