Math111i_GroupQuiz2_Solutions

Math111i_GroupQuiz2_Solutions - form. That follows as-2 x +...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Math 111I Sec 001 Group Quiz 2 Name Directions: Read each question carefully and answer in the space pro- vided. The use of calculators is allowed, but not necessary. There are 10 points possible. To receive partial credit on any problem work must be shown. 1. y is directly proportional to x , and when y = 17 . 4 we have that x = 6. A) Find a formula to describe y as a function of x . B) Use this formula to find y when x is 8. Solutions. A) The definition to directly proportional tells us that our line looks like y = kx, or that the point (0 , 0) lies on our line. So we find the equation of the line through (6 , 17 . 4) and (0 , 0) which follows as y = 17 . 4 6 x = 2 . 9 x. B) Now we have y = 2 . 9 x , or if we wanted to to express y as a function of x , y = f ( x ) = 2 . 9 x . Question B) asks us to compute f (8), and we do so to find f (8) = 2 . 9(8) = 23 . 2 . 2. Determine whether the two lines are perpendicular - 2 x + 7 y = 9 and 8 x - 4 y = 9. Show your work and state whether they are perpendicular or not. Solutions. We begin by algebraically manipulating the two equations to y = mx + b
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 2
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: form. That follows as-2 x + 7 y = 9 7 y = 2 x + 9 y = 2 7 x + 9 7 , Math 111I Sec 001 Group Quiz 2 and 8 x-4 y = 9-4 y =-8 x + 9 y =-8-4 x-9 4 y = 2 x-9 4 . Now because 2 6 =-7 2 we have that our two lines cannot be perpendicular. 3. Determine whether the following data is linear. If it is linear, nd the function and write your answer in the form y = mx + b . If the data is not linear then state that. x y-5 8-4 5-3 2-2-1-7 Solutions. It is easy to compute the average rates of change for every interval m [-5 ,-4] ,m [-4 ,-3] ,m [-3 ,-2] , and m [-2 , 0] . For example m [-4 ,-3] = 5-2-4-(-3) =-3 . But more importantly the tricky value to compute is m [-2 , 0] =-1-(-7)-2-= 6-2 =-3 . So we have that our function is linear with a slope of m =-3, and we are given the y-intercept as (0 ,-7). Thus the equation of our line is y =-3 x-7 , and we are done....
View Full Document

Page1 / 2

Math111i_GroupQuiz2_Solutions - form. That follows as-2 x +...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online