Differential Equation for a curve from a given point.
$begingroup$
Question,
The y intercept of the tangent line to a curve at any point is always
equal to the slope at that point. If the curve passes through the point
(2, 1), find the equation of the curve.
Based off this little information I have $y=y'x+b$ where $b$ would be $y'$ evaluated at the point. I'm not sure how to get this into an equation for a curve or if there is a much better approach. Thanks in advance.
ordinary-differential-equations
$endgroup$
add a comment |
$begingroup$
Question,
The y intercept of the tangent line to a curve at any point is always
equal to the slope at that point. If the curve passes through the point
(2, 1), find the equation of the curve.
Based off this little information I have $y=y'x+b$ where $b$ would be $y'$ evaluated at the point. I'm not sure how to get this into an equation for a curve or if there is a much better approach. Thanks in advance.
ordinary-differential-equations
$endgroup$
add a comment |
$begingroup$
Question,
The y intercept of the tangent line to a curve at any point is always
equal to the slope at that point. If the curve passes through the point
(2, 1), find the equation of the curve.
Based off this little information I have $y=y'x+b$ where $b$ would be $y'$ evaluated at the point. I'm not sure how to get this into an equation for a curve or if there is a much better approach. Thanks in advance.
ordinary-differential-equations
$endgroup$
Question,
The y intercept of the tangent line to a curve at any point is always
equal to the slope at that point. If the curve passes through the point
(2, 1), find the equation of the curve.
Based off this little information I have $y=y'x+b$ where $b$ would be $y'$ evaluated at the point. I'm not sure how to get this into an equation for a curve or if there is a much better approach. Thanks in advance.
ordinary-differential-equations
ordinary-differential-equations
asked Dec 11 '13 at 7:42
slow_Mathslow_Math
64
64
add a comment |
add a comment |
1 Answer
1
active
oldest
votes
$begingroup$
If you fix a point $x_0$ the equation of the tangent line in $(x_0,f(x_0))$ is
$$
y = f(x_0) + f'(x_0)(x-x_0) = f'(x_0) x + f(x_0) - f'(x_0) x_0
$$
hence $q=f(x_0)-f'(x_0)x_0$ is the intercept, and the equation is (call $x=x_0$, $y=f(x_0)$
$$
y' = y - y'x
$$
i.e.
$$
y'(1+x) = y
$$
i.e.
$$
frac{y'}{y} = frac{1}{1+x}
$$
Can you solve this?
$endgroup$
$begingroup$
Thanks! Yeah I believe so, trying it now, integrating both sides and solving for y.
$endgroup$
– slow_Math
Dec 11 '13 at 8:01
add a comment |
Your Answer
StackExchange.ifUsing("editor", function () {
return StackExchange.using("mathjaxEditing", function () {
StackExchange.MarkdownEditor.creationCallbacks.add(function (editor, postfix) {
StackExchange.mathjaxEditing.prepareWmdForMathJax(editor, postfix, [["$", "$"], ["\\(","\\)"]]);
});
});
}, "mathjax-editing");
StackExchange.ready(function() {
var channelOptions = {
tags: "".split(" "),
id: "69"
};
initTagRenderer("".split(" "), "".split(" "), channelOptions);
StackExchange.using("externalEditor", function() {
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled) {
StackExchange.using("snippets", function() {
createEditor();
});
}
else {
createEditor();
}
});
function createEditor() {
StackExchange.prepareEditor({
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: true,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: 10,
bindNavPrevention: true,
postfix: "",
imageUploader: {
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
},
noCode: true, onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
});
}
});
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f602478%2fdifferential-equation-for-a-curve-from-a-given-point%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
$begingroup$
If you fix a point $x_0$ the equation of the tangent line in $(x_0,f(x_0))$ is
$$
y = f(x_0) + f'(x_0)(x-x_0) = f'(x_0) x + f(x_0) - f'(x_0) x_0
$$
hence $q=f(x_0)-f'(x_0)x_0$ is the intercept, and the equation is (call $x=x_0$, $y=f(x_0)$
$$
y' = y - y'x
$$
i.e.
$$
y'(1+x) = y
$$
i.e.
$$
frac{y'}{y} = frac{1}{1+x}
$$
Can you solve this?
$endgroup$
$begingroup$
Thanks! Yeah I believe so, trying it now, integrating both sides and solving for y.
$endgroup$
– slow_Math
Dec 11 '13 at 8:01
add a comment |
$begingroup$
If you fix a point $x_0$ the equation of the tangent line in $(x_0,f(x_0))$ is
$$
y = f(x_0) + f'(x_0)(x-x_0) = f'(x_0) x + f(x_0) - f'(x_0) x_0
$$
hence $q=f(x_0)-f'(x_0)x_0$ is the intercept, and the equation is (call $x=x_0$, $y=f(x_0)$
$$
y' = y - y'x
$$
i.e.
$$
y'(1+x) = y
$$
i.e.
$$
frac{y'}{y} = frac{1}{1+x}
$$
Can you solve this?
$endgroup$
$begingroup$
Thanks! Yeah I believe so, trying it now, integrating both sides and solving for y.
$endgroup$
– slow_Math
Dec 11 '13 at 8:01
add a comment |
$begingroup$
If you fix a point $x_0$ the equation of the tangent line in $(x_0,f(x_0))$ is
$$
y = f(x_0) + f'(x_0)(x-x_0) = f'(x_0) x + f(x_0) - f'(x_0) x_0
$$
hence $q=f(x_0)-f'(x_0)x_0$ is the intercept, and the equation is (call $x=x_0$, $y=f(x_0)$
$$
y' = y - y'x
$$
i.e.
$$
y'(1+x) = y
$$
i.e.
$$
frac{y'}{y} = frac{1}{1+x}
$$
Can you solve this?
$endgroup$
If you fix a point $x_0$ the equation of the tangent line in $(x_0,f(x_0))$ is
$$
y = f(x_0) + f'(x_0)(x-x_0) = f'(x_0) x + f(x_0) - f'(x_0) x_0
$$
hence $q=f(x_0)-f'(x_0)x_0$ is the intercept, and the equation is (call $x=x_0$, $y=f(x_0)$
$$
y' = y - y'x
$$
i.e.
$$
y'(1+x) = y
$$
i.e.
$$
frac{y'}{y} = frac{1}{1+x}
$$
Can you solve this?
answered Dec 11 '13 at 7:48
Emanuele PaoliniEmanuele Paolini
17.9k22052
17.9k22052
$begingroup$
Thanks! Yeah I believe so, trying it now, integrating both sides and solving for y.
$endgroup$
– slow_Math
Dec 11 '13 at 8:01
add a comment |
$begingroup$
Thanks! Yeah I believe so, trying it now, integrating both sides and solving for y.
$endgroup$
– slow_Math
Dec 11 '13 at 8:01
$begingroup$
Thanks! Yeah I believe so, trying it now, integrating both sides and solving for y.
$endgroup$
– slow_Math
Dec 11 '13 at 8:01
$begingroup$
Thanks! Yeah I believe so, trying it now, integrating both sides and solving for y.
$endgroup$
– slow_Math
Dec 11 '13 at 8:01
add a comment |
Thanks for contributing an answer to Mathematics Stack Exchange!
- Please be sure to answer the question. Provide details and share your research!
But avoid …
- Asking for help, clarification, or responding to other answers.
- Making statements based on opinion; back them up with references or personal experience.
Use MathJax to format equations. MathJax reference.
To learn more, see our tips on writing great answers.
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f602478%2fdifferential-equation-for-a-curve-from-a-given-point%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown