Difference between revisions of "1950 AHSME Problems/Problem 44"

m (Problem)
Line 3: Line 3:
 
The graph of <math> y\equal{}\log x</math>
 
The graph of <math> y\equal{}\log x</math>
  
<math>\textbf{(A)}\text{Cuts the }y\text{-axis} \qquad\\
+
<math>\textbf{(A)}\ \text{Cuts the }y\text{-axis} \qquad\\
 
\textbf{(B)}\ \text{Cuts all lines perpendicular to the }x\text{-axis} \qquad\\
 
\textbf{(B)}\ \text{Cuts all lines perpendicular to the }x\text{-axis} \qquad\\
 
\textbf{(C)}\ \text{Cuts the }x\text{-axis} \qquad\\
 
\textbf{(C)}\ \text{Cuts the }x\text{-axis} \qquad\\
 
\textbf{(D)}\ \text{Cuts neither axis} \qquad\\
 
\textbf{(D)}\ \text{Cuts neither axis} \qquad\\
 
\textbf{(E)}\ \text{Cuts all circles whose center is at the origin}</math>
 
\textbf{(E)}\ \text{Cuts all circles whose center is at the origin}</math>
 +
 
== Solution ==
 
== Solution ==
 
The domain of <math>\log x</math> is the set of all positive reals, so the graph of <math>y=\log x</math> clearly doesn't cut the <math>y</math>-axis. It therefore doesn't cut every line perpendicular to the <math>x</math>-axis. It does however cut the <math>x</math>-axis at <math>(1,0)</math>. In addition, if one examines the graph of <math>y=\log x</math>, one can clearly see that there are many circles centered at the origin that do not intersect the graph of <math>y=\log x</math>. Therefore the answer is <math>\boxed{\textbf{(C)}\ \text{Cuts the }x\text{-axis}}</math>.
 
The domain of <math>\log x</math> is the set of all positive reals, so the graph of <math>y=\log x</math> clearly doesn't cut the <math>y</math>-axis. It therefore doesn't cut every line perpendicular to the <math>x</math>-axis. It does however cut the <math>x</math>-axis at <math>(1,0)</math>. In addition, if one examines the graph of <math>y=\log x</math>, one can clearly see that there are many circles centered at the origin that do not intersect the graph of <math>y=\log x</math>. Therefore the answer is <math>\boxed{\textbf{(C)}\ \text{Cuts the }x\text{-axis}}</math>.

Revision as of 00:19, 2 October 2014

Problem

The graph of $y\equal{}\log x$ (Error compiling LaTeX. Unknown error_msg)

$\textbf{(A)}\ \text{Cuts the }y\text{-axis} \qquad\\ \textbf{(B)}\ \text{Cuts all lines perpendicular to the }x\text{-axis} \qquad\\ \textbf{(C)}\ \text{Cuts the }x\text{-axis} \qquad\\ \textbf{(D)}\ \text{Cuts neither axis} \qquad\\ \textbf{(E)}\ \text{Cuts all circles whose center is at the origin}$

Solution

The domain of $\log x$ is the set of all positive reals, so the graph of $y=\log x$ clearly doesn't cut the $y$-axis. It therefore doesn't cut every line perpendicular to the $x$-axis. It does however cut the $x$-axis at $(1,0)$. In addition, if one examines the graph of $y=\log x$, one can clearly see that there are many circles centered at the origin that do not intersect the graph of $y=\log x$. Therefore the answer is $\boxed{\textbf{(C)}\ \text{Cuts the }x\text{-axis}}$.


An image is supposed to go here. You can help us out by creating one and editing it in. Thanks.


See Also

1950 AHSC (ProblemsAnswer KeyResources)
Preceded by
Problem 43
Followed by
Problem 45
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
All AHSME Problems and Solutions

The problems on this page are copyrighted by the Mathematical Association of America's American Mathematics Competitions. AMC logo.png