
EBK NATURE OF MATHEMATICS
13th Edition
ISBN: 9781305855588
Author: SMITH
Publisher: CENGAGE CO
expand_more
expand_more
format_list_bulleted
Question
Chapter 7.CR, Problem 20CR
To determine
To find:
The reason for Saccheri quadrilateral leads to different kinds of geometries.
Expert Solution & Answer

Want to see the full answer?
Check out a sample textbook solution
Students have asked these similar questions
12. Suppose that a, b E R and a < b. Show that the vector space C[a, b] of all continuous complex
valued functions defined on [a, b], with supremum norm
is a Banach space.
Ilflloc:
=
sup f(t),
t€[a,b]
O Functions
Composition of two functions: Domain and...
Two functions ƒ and g are defined in the figure below.
76
2
8
5
7
8
19
8
9
Domain of f
Range of f
Domain of g
Range of g
3/5
Anthony
Find the domain and range of the composition g.f. Write your answers in set
notation.
(a) Domain of gof: ☐
(b)
Range of gof: ☐
Х
Explanation
Check
0,0,...
Español
لكا
©2025 McGraw Hill LLC. All Rights Reserved Torms of lico
Privacy Contor
Accessibility.
Two functions ƒ and g are defined in the figure below.
g
6
6
7
8
8
8
9
Domain of f
Range of f
Domain of g
Range of g
Find the domain and range of the composition g.f. Write your answers in set
notation.
(a) Domain of gof:
(b)
Range of gof: ☐
☑
0,0,...
Chapter 7 Solutions
EBK NATURE OF MATHEMATICS
Ch. 7.1 - Is the woman in the figure a young woman or an old...Ch. 7.1 - Is the fly in the Figure 7.11 on the cube or in...Ch. 7.1 - Prob. 3PSCh. 7.1 - Prob. 4PSCh. 7.1 - Prob. 5PSCh. 7.1 - Prob. 6PSCh. 7.1 - Prob. 7PSCh. 7.1 - Prob. 8PSCh. 7.1 - Prob. 9PSCh. 7.1 - Prob. 10PS
Ch. 7.1 - Prob. 11PSCh. 7.1 - Prob. 12PSCh. 7.1 - Prob. 13PSCh. 7.1 - Prob. 14PSCh. 7.1 - Prob. 15PSCh. 7.1 - Prob. 16PSCh. 7.1 - Prob. 17PSCh. 7.1 - Prob. 18PSCh. 7.1 - Use the illustration in Figure 7.12 to draw the...Ch. 7.1 - Prob. 20PSCh. 7.1 - Prob. 21PSCh. 7.1 - Prob. 22PSCh. 7.1 - Prob. 23PSCh. 7.1 - Prob. 24PSCh. 7.1 - Prob. 25PSCh. 7.1 - Prob. 26PSCh. 7.1 - Prob. 27PSCh. 7.1 - Carry out the constructions requested in Problems...Ch. 7.1 - Prob. 29PSCh. 7.1 - Prob. 30PSCh. 7.1 - Prob. 31PSCh. 7.1 - Prob. 32PSCh. 7.1 - Prob. 33PSCh. 7.1 - Prob. 34PSCh. 7.1 - Prob. 35PSCh. 7.1 - Prob. 36PSCh. 7.1 - Prob. 37PSCh. 7.1 - Prob. 38PSCh. 7.1 - Prob. 39PSCh. 7.1 - Prob. 40PSCh. 7.1 - Prob. 41PSCh. 7.1 - Prob. 42PSCh. 7.1 - Prob. 43PSCh. 7.1 - Prob. 44PSCh. 7.1 - Prob. 45PSCh. 7.1 - Prob. 46PSCh. 7.1 - Prob. 47PSCh. 7.1 - Prob. 48PSCh. 7.1 - Prob. 49PSCh. 7.1 - Prob. 50PSCh. 7.1 - Prob. 51PSCh. 7.1 - Study the patterns shown in Figure 7.13. When...Ch. 7.1 - Prob. 53PSCh. 7.1 - Prob. 54PSCh. 7.1 - Prob. 55PSCh. 7.1 - Prob. 56PSCh. 7.1 - Prob. 57PSCh. 7.1 - Prob. 58PSCh. 7.1 - The letters of the alphabet can be sorted into the...Ch. 7.1 - Prob. 60PSCh. 7.2 - Prob. 1PSCh. 7.2 - Prob. 2PSCh. 7.2 - Prob. 3PSCh. 7.2 - Prob. 4PSCh. 7.2 - Prob. 5PSCh. 7.2 - Prob. 6PSCh. 7.2 - Prob. 7PSCh. 7.2 - Prob. 8PSCh. 7.2 - Prob. 9PSCh. 7.2 - Prob. 10PSCh. 7.2 - Prob. 11PSCh. 7.2 - Prob. 12PSCh. 7.2 - Determine whether each sentence in Problems 11 14...Ch. 7.2 - Prob. 14PSCh. 7.2 - Prob. 15PSCh. 7.2 - Prob. 16PSCh. 7.2 - Prob. 17PSCh. 7.2 - Prob. 18PSCh. 7.2 - Prob. 19PSCh. 7.2 - Prob. 20PSCh. 7.2 - Prob. 21PSCh. 7.2 - Prob. 22PSCh. 7.2 - Prob. 23PSCh. 7.2 - Prob. 24PSCh. 7.2 - In Problems 25 32, classify the pairs of angles...Ch. 7.2 - Prob. 26PSCh. 7.2 - Prob. 27PSCh. 7.2 - Prob. 28PSCh. 7.2 - In Problems 25 32, classify the pairs of angles...Ch. 7.2 - Prob. 30PSCh. 7.2 - Prob. 31PSCh. 7.2 - Prob. 32PSCh. 7.2 - Prob. 33PSCh. 7.2 - Prob. 34PSCh. 7.2 - Prob. 35PSCh. 7.2 - Prob. 36PSCh. 7.2 - Prob. 37PSCh. 7.2 - Prob. 38PSCh. 7.2 - Prob. 39PSCh. 7.2 - Prob. 40PSCh. 7.2 - Prob. 41PSCh. 7.2 - Prob. 42PSCh. 7.2 - Prob. 43PSCh. 7.2 - Prob. 44PSCh. 7.2 - Prob. 45PSCh. 7.2 - Prob. 46PSCh. 7.2 - Prob. 47PSCh. 7.2 - Prob. 48PSCh. 7.2 - Prob. 49PSCh. 7.2 - Prob. 50PSCh. 7.2 - Prob. 51PSCh. 7.2 - In Problems 52 57, find the measures of all the...Ch. 7.2 - Prob. 53PSCh. 7.2 - Prob. 54PSCh. 7.2 - Prob. 55PSCh. 7.2 - Prob. 56PSCh. 7.2 - Prob. 57PSCh. 7.2 - Prob. 58PSCh. 7.2 - Prob. 59PSCh. 7.2 - Historical Quest: Allow me to start you on a...Ch. 7.3 - IN YOUR OWN WORDS What is a triangle?Ch. 7.3 - Prob. 2PSCh. 7.3 - IN YOUR OWN WORDS Explain the notation ABCDEF.Ch. 7.3 - Prob. 4PSCh. 7.3 - Prob. 5PSCh. 7.3 - Prob. 6PSCh. 7.3 - Prob. 7PSCh. 7.3 - Prob. 8PSCh. 7.3 - Prob. 9PSCh. 7.3 - Name the corresponding parts of the triangles in...Ch. 7.3 - In Problems 11-16, find the measure of the third...Ch. 7.3 - Prob. 12PSCh. 7.3 - Prob. 13PSCh. 7.3 - Prob. 14PSCh. 7.3 - Prob. 15PSCh. 7.3 - Prob. 16PSCh. 7.3 - Prob. 17PSCh. 7.3 - Prob. 18PSCh. 7.3 - Prob. 19PSCh. 7.3 - Prob. 20PSCh. 7.3 - Prob. 21PSCh. 7.3 - Prob. 22PSCh. 7.3 - Prob. 23PSCh. 7.3 - Prob. 24PSCh. 7.3 - Prob. 25PSCh. 7.3 - Prob. 26PSCh. 7.3 - Prob. 27PSCh. 7.3 - Prob. 28PSCh. 7.3 - Prob. 29PSCh. 7.3 - Prob. 30PSCh. 7.3 - Prob. 31PSCh. 7.3 - Prob. 32PSCh. 7.3 - Prob. 33PSCh. 7.3 - Prob. 34PSCh. 7.3 - Use algebra to find the value of x in each of the...Ch. 7.3 - Prob. 36PSCh. 7.3 - Prob. 37PSCh. 7.3 - Use algebra to find the value of x in each of the...Ch. 7.3 - Prob. 39PSCh. 7.3 - Prob. 40PSCh. 7.3 - Prob. 41PSCh. 7.3 - Prob. 42PSCh. 7.3 - Prob. 43PSCh. 7.3 - Prob. 44PSCh. 7.3 - Prob. 45PSCh. 7.3 - Prob. 46PSCh. 7.3 - Prob. 47PSCh. 7.3 - Prob. 48PSCh. 7.3 - Prob. 49PSCh. 7.3 - Prob. 50PSCh. 7.3 - Prob. 51PSCh. 7.3 - Prob. 52PSCh. 7.3 - Prob. 53PSCh. 7.3 - Prob. 54PSCh. 7.3 - Prob. 55PSCh. 7.3 - Prob. 56PSCh. 7.3 - The legs of a picnic table form a triangle where...Ch. 7.3 - Prob. 58PSCh. 7.3 - Prob. 59PSCh. 7.3 - Prob. 60PSCh. 7.4 - IN YOUR OWN WORDS Contrast congruent and similar...Ch. 7.4 - Prob. 2PSCh. 7.4 - In Problems 3-8, determine if the triangles are...Ch. 7.4 - Prob. 4PSCh. 7.4 - Prob. 5PSCh. 7.4 - Prob. 6PSCh. 7.4 - Prob. 7PSCh. 7.4 - Prob. 8PSCh. 7.4 - Prob. 9PSCh. 7.4 - Prob. 10PSCh. 7.4 - Prob. 11PSCh. 7.4 - Prob. 12PSCh. 7.4 - Prob. 13PSCh. 7.4 - Prob. 14PSCh. 7.4 - Prob. 15PSCh. 7.4 - Prob. 16PSCh. 7.4 - Prob. 17PSCh. 7.4 - Prob. 18PSCh. 7.4 - Prob. 19PSCh. 7.4 - Prob. 20PSCh. 7.4 - Prob. 21PSCh. 7.4 - Prob. 22PSCh. 7.4 - Prob. 23PSCh. 7.4 - Prob. 24PSCh. 7.4 - Prob. 25PSCh. 7.4 - Prob. 26PSCh. 7.4 - Prob. 27PSCh. 7.4 - Prob. 28PSCh. 7.4 - Prob. 29PSCh. 7.4 - Each figure in Problems 29-34 contains two similar...Ch. 7.4 - Prob. 31PSCh. 7.4 - Prob. 32PSCh. 7.4 - Prob. 33PSCh. 7.4 - Prob. 34PSCh. 7.4 - Prob. 35PSCh. 7.4 - Prob. 36PSCh. 7.4 - Given AC is perpendicular to MB, and ABC is an...Ch. 7.4 - Prob. 38PSCh. 7.4 - Prob. 39PSCh. 7.4 - Prob. 40PSCh. 7.4 - Use similar triangles and a proportion to find the...Ch. 7.4 - Prob. 42PSCh. 7.4 - Prob. 43PSCh. 7.4 - Prob. 44PSCh. 7.4 - Prob. 45PSCh. 7.4 - Prob. 46PSCh. 7.4 - A bell tower casts a shadow 45ft long. At the same...Ch. 7.4 - Prob. 48PSCh. 7.4 - Prob. 49PSCh. 7.4 - Prob. 50PSCh. 7.4 - Prob. 51PSCh. 7.4 - Prob. 52PSCh. 7.4 - Prob. 53PSCh. 7.4 - Prob. 54PSCh. 7.4 - Prob. 55PSCh. 7.4 - Suppose a 6- ft person wishes to determine the...Ch. 7.4 - Prob. 57PSCh. 7.4 - Prob. 58PSCh. 7.4 - Prob. 59PSCh. 7.4 - Prob. 60PSCh. 7.5 - Prob. 1PSCh. 7.5 - Prob. 2PSCh. 7.5 - Prob. 3PSCh. 7.5 - Prob. 4PSCh. 7.5 - Prob. 5PSCh. 7.5 - Prob. 6PSCh. 7.5 - Prob. 7PSCh. 7.5 - Prob. 8PSCh. 7.5 - Prob. 9PSCh. 7.5 - Prob. 10PSCh. 7.5 - Prob. 11PSCh. 7.5 - Prob. 12PSCh. 7.5 - Prob. 13PSCh. 7.5 - Prob. 14PSCh. 7.5 - Prob. 15PSCh. 7.5 - Prob. 16PSCh. 7.5 - Prob. 17PSCh. 7.5 - Prob. 18PSCh. 7.5 - Prob. 19PSCh. 7.5 - Prob. 20PSCh. 7.5 - Prob. 21PSCh. 7.5 - Prob. 22PSCh. 7.5 - Prob. 23PSCh. 7.5 - Prob. 24PSCh. 7.5 - Prob. 25PSCh. 7.5 - Prob. 26PSCh. 7.5 - Prob. 27PSCh. 7.5 - Prob. 28PSCh. 7.5 - Prob. 29PSCh. 7.5 - Prob. 30PSCh. 7.5 - Prob. 31PSCh. 7.5 - Prob. 32PSCh. 7.5 - Prob. 33PSCh. 7.5 - Prob. 34PSCh. 7.5 - Prob. 35PSCh. 7.5 - Prob. 36PSCh. 7.5 - Prob. 37PSCh. 7.5 - Prob. 38PSCh. 7.5 - Prob. 39PSCh. 7.5 - Prob. 40PSCh. 7.5 - Prob. 41PSCh. 7.5 - Prob. 42PSCh. 7.5 - Prob. 43PSCh. 7.5 - Prob. 44PSCh. 7.5 - Prob. 45PSCh. 7.5 - Prob. 46PSCh. 7.5 - Prob. 47PSCh. 7.5 - Level 2 If the angle from the horizontal to the...Ch. 7.5 - Prob. 49PSCh. 7.5 - Prob. 50PSCh. 7.5 - Prob. 51PSCh. 7.5 - Prob. 52PSCh. 7.5 - Prob. 53PSCh. 7.5 - Prob. 54PSCh. 7.5 - Prob. 55PSCh. 7.5 - Prob. 56PSCh. 7.5 - Prob. 57PSCh. 7.5 - Prob. 58PSCh. 7.5 - Prob. 59PSCh. 7.5 - Problem solving Level 3 a. If the distance from...Ch. 7.6 - Prob. 1PSCh. 7.6 - Prob. 2PSCh. 7.6 - Prob. 3PSCh. 7.6 - Prob. 4PSCh. 7.6 - Prob. 5PSCh. 7.6 - Prob. 6PSCh. 7.6 - Prob. 7PSCh. 7.6 - Prob. 8PSCh. 7.6 - Prob. 9PSCh. 7.6 - Prob. 10PSCh. 7.6 - Prob. 11PSCh. 7.6 - Prob. 12PSCh. 7.6 - Name the geometry Euclidean, elliptic, or...Ch. 7.6 - Prob. 14PSCh. 7.6 - Prob. 15PSCh. 7.6 - Prob. 16PSCh. 7.6 - Prob. 17PSCh. 7.6 - Prob. 18PSCh. 7.6 - Prob. 19PSCh. 7.6 - Prob. 20PSCh. 7.6 - Prob. 21PSCh. 7.6 - Prob. 22PSCh. 7.6 - Prob. 23PSCh. 7.6 - Prob. 24PSCh. 7.6 - Prob. 25PSCh. 7.6 - Prob. 26PSCh. 7.6 - Prob. 27PSCh. 7.6 - Prob. 28PSCh. 7.6 - Consider the top, front, and side views as shown...Ch. 7.6 - Prob. 30PSCh. 7.6 - Prob. 31PSCh. 7.6 - Prob. 32PSCh. 7.6 - Prob. 33PSCh. 7.6 - Prob. 34PSCh. 7.6 - Prob. 35PSCh. 7.6 - Prob. 36PSCh. 7.6 - Prob. 37PSCh. 7.6 - Prob. 38PSCh. 7.6 - Prob. 39PSCh. 7.6 - Prob. 40PSCh. 7.6 - Prob. 41PSCh. 7.6 - Prob. 42PSCh. 7.6 - Prob. 43PSCh. 7.6 - Prob. 44PSCh. 7.6 - Prob. 45PSCh. 7.6 - Prob. 46PSCh. 7.6 - Prob. 47PSCh. 7.6 - Prob. 48PSCh. 7.6 - Prob. 49PSCh. 7.6 - Prob. 50PSCh. 7.6 - Prob. 51PSCh. 7.6 - Prob. 52PSCh. 7.6 - Prob. 53PSCh. 7.6 - Prob. 54PSCh. 7.6 - When is an open book a closed book? If the...Ch. 7.6 - Prob. 56PSCh. 7.6 - Prob. 57PSCh. 7.6 - Prob. 58PSCh. 7.6 - Prob. 59PSCh. 7.CR - Prob. 1CRCh. 7.CR - Prob. 2CRCh. 7.CR - Prob. 3CRCh. 7.CR - Prob. 4CRCh. 7.CR - Prob. 5CRCh. 7.CR - Prob. 6CRCh. 7.CR - 7. Bourbon Palace Figure 7.77 is home to the...Ch. 7.CR - Prob. 8CRCh. 7.CR - Prob. 9CRCh. 7.CR - Prob. 10CRCh. 7.CR - Prob. 11CRCh. 7.CR - Prob. 12CRCh. 7.CR - Prob. 13CRCh. 7.CR - Prob. 14CRCh. 7.CR - Prob. 15CRCh. 7.CR - Prob. 16CRCh. 7.CR - Prob. 17CRCh. 7.CR - Prob. 18CRCh. 7.CR - Prob. 19CRCh. 7.CR - Prob. 20CR
Knowledge Booster
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, subject and related others by exploring similar questions and additional content below.Similar questions
- The table below shows the estimated effects for a logistic regression model with squamous cell esophageal cancer (Y = 1, yes; Y = 0, no) as the response. Smoking status (S) equals 1 for at least one pack per day and 0 otherwise, alcohol consumption (A) equals the average number of alcohoic drinks consumed per day, and race (R) equals 1 for blacks and 0 for whites. Variable Effect (β) P-value Intercept -7.00 <0.01 Alcohol use 0.10 0.03 Smoking 1.20 <0.01 Race 0.30 0.02 Race × smoking 0.20 0.04 Write-out the prediction equation (i.e., the logistic regression model) when R = 0 and again when R = 1. Find the fitted Y S conditional odds ratio in each case. Next, write-out the logistic regression model when S = 0 and again when S = 1. Find the fitted Y R conditional odds ratio in each case.arrow_forwardThe chi-squared goodness-of-fit test can be used to test if data comes from a specific continuous distribution by binning the data to make it categorical. Using the OpenIntro Statistics county_complete dataset, test the hypothesis that the persons_per_household 2019 values come from a normal distribution with mean and standard deviation equal to that variable's mean and standard deviation. Use signficance level a = 0.01. In your solution you should 1. Formulate the hypotheses 2. Fill in this table Range (-⁰⁰, 2.34] (2.34, 2.81] (2.81, 3.27] (3.27,00) Observed 802 Expected 854.2 The first row has been filled in. That should give you a hint for how to calculate the expected frequencies. Remember that the expected frequencies are calculated under the assumption that the null hypothesis is true. FYI, the bounderies for each range were obtained using JASP's drag-and-drop cut function with 8 levels. Then some of the groups were merged. 3. Check any conditions required by the chi-squared…arrow_forwardDone Oli ○ Functions Composition of two functions: Domain and range Two functions 0 g 3 4 6 www-awy.aleks.com g and ƒ are defined in the figure below. 8 8 9 Domain of g Range of g Domain of f Range of f 0/5 Anthony Find the domain and range of the composition f.g. Write your answers in set notation. (a) Domain of fog: ☐ (b) Range of fog: ☐ Х Explanation Check 0,0,... Español © 2025 McGraw HillLLC. AIL Rights Reserved Terms of Use | Privacy Center Accessibilityarrow_forward
- Solve the following systems using Gauss Seidal and Jacobi iteration methods for n=8 and initial values Xº=(000). - 3x1 + 2x2 x3 = 4 - 2x1 x2+2x3 = 10 x13x24x3 = 4arrow_forwardA gardener has ten different potted plants, and they are spraying the plants with doses offertilizers. Plants can receive zero or more doses in a session. In the following, we count eachpossible number of doses the ten plants can receive (the order of spraying in a session doesnot matter). How many ways are there to do two sessions of spraying, where each plant receives atmost two doses total?arrow_forwardQ/Consider the set 8 e' = { x = (x\ 1 X 2 1 X3, ...) € (°: { \x;k< ∞ } Show that M & XII, Ixil = にし i= 1 defines a norm onarrow_forward
- vector Q/Consider the real vector space R². For every X= (X/X2) ER². Let 11x11 = \xil+\x\. Show that 1.11 define a hormon R².arrow_forward12. Suppose that a, b E R and a < b. Show that the vector space C[a, b] of all continuous complex valued functions defined on [a, b], with supremum norm is a Banach space. Ilflloc: = sup f(t), t€[a,b]arrow_forwardbrayden knows that his distance from earth to pluto 5.9 times....arrow_forward
- C. Since C SNEN 2. Suppose that V and Ware vector spaces over F. Consider the cartesian product V x W, with vector addition and scalar multiplication defined by (V1.W)+(V2, W2) (V1+V2, W₁ + W₂) for every (V1, W1). (V2, W2) EV x W and e€ F. a) Show that V x W is a vector space over F. and (v, w) (cv,₁) b) Suppose that || ||v is a norm on V and || ||w is a norm on W. Show that (v, w) defines a norm on V x W. vy+wwarrow_forwardSolve the following nonlinear system using Newton's method 1 f1(x1, x2, x3)=3x₁ = cos(x2x3) - - 2 f2(x1, x2, x3) = x² - 81(x2 +0.1)² + sin x3 + 1.06 f3(x1, x2, x3) = ex1x2 +20x3 + Using x (0) X1 X2 X3 10π-3 3 = 0.1, 0.1, 0.1 as initial conditioarrow_forwardUse the graph of the function y = g(x) below to answer the questions. y' -5 -4 4- 3- 27 -2 -3+ -4 x 4 (a) Is g(-2) negative? Yes No (b) For which value(s) of x is g(x) > 0? Write your answer using interval notation. ☐ (c) For which value(s) of x is g(x) = 0? If there is more than one value, separate them with commas. 0,0... (0,0) (0,0) (0,0) (0,0) OVO 0arrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
- Holt Mcdougal Larson Pre-algebra: Student Edition...AlgebraISBN:9780547587776Author:HOLT MCDOUGALPublisher:HOLT MCDOUGALElementary Geometry For College Students, 7eGeometryISBN:9781337614085Author:Alexander, Daniel C.; Koeberlein, Geralyn M.Publisher:Cengage,Elementary Geometry for College StudentsGeometryISBN:9781285195698Author:Daniel C. Alexander, Geralyn M. KoeberleinPublisher:Cengage Learning
- Elementary Linear Algebra (MindTap Course List)AlgebraISBN:9781305658004Author:Ron LarsonPublisher:Cengage LearningAlgebra & Trigonometry with Analytic GeometryAlgebraISBN:9781133382119Author:SwokowskiPublisher:Cengage

Holt Mcdougal Larson Pre-algebra: Student Edition...
Algebra
ISBN:9780547587776
Author:HOLT MCDOUGAL
Publisher:HOLT MCDOUGAL

Elementary Geometry For College Students, 7e
Geometry
ISBN:9781337614085
Author:Alexander, Daniel C.; Koeberlein, Geralyn M.
Publisher:Cengage,

Elementary Geometry for College Students
Geometry
ISBN:9781285195698
Author:Daniel C. Alexander, Geralyn M. Koeberlein
Publisher:Cengage Learning

Elementary Linear Algebra (MindTap Course List)
Algebra
ISBN:9781305658004
Author:Ron Larson
Publisher:Cengage Learning
Algebra & Trigonometry with Analytic Geometry
Algebra
ISBN:9781133382119
Author:Swokowski
Publisher:Cengage

Quadrilaterals: Missing Angles and Sides; Author: rhornfeck;https://www.youtube.com/watch?v=knVj1O0L2TM;License: Standard YouTube License, CC-BY
STD IX | State Board | Types of Quadrilateral; Author: Robomate;https://www.youtube.com/watch?v=wh0KQ4UB0EU;License: Standard YouTube License, CC-BY