Find the best tutors and institutes for Class 12 Tuition
Q2:
Find the differential equation of all non vertical lines in a plane.
Solution :
Step 1: Establishing the General Equation of the Family of Curves
The general equation for any non-vertical line in a Cartesian plane is expressed in the slope-intercept form:
$y = mx + c$
Where:
- $m$ represents the slope of the line (a constant parameter).
- $c$ represents the y-intercept of the line (a constant parameter).
- $x$ and $y$ are the coordinate variables.
[By the definition of linear functions in Euclidean geometry, a non-vertical line is uniquely determined by two independent constants, $m$ and $c$.]
Step 2: First-Order Differentiation
To eliminate the constants, we differentiate the equation with respect to $x$:
$\frac{d}{dx}(y) = \frac{d}{dx}(mx + c)$
$\frac{dy}{dx} = m$
[Per the Power Rule and the Constant Rule of differentiation, where $\frac{d}{dx}(mx) = m$ and $\frac{d}{dx}(c) = 0$.]
Step 3: Second-Order Differentiation
Since we have two arbitrary constants ($m$ and $c$), we must differentiate a second time to eliminate $m$:
$\frac{d}{dx}\left(\frac{dy}{dx}\right) = \frac{d}{dx}(m)$
$\frac{d^2y}{dx^2} = 0$
[Per the Derivative of a Constant Rule, the derivative of any constant $m$ with respect to $x$ is $0$.]
Step 4: Geometric Visualization
Step 5: Final Resultant Differential Equation
The elimination of arbitrary constants $m$ and $c$ results in a second-order linear homogeneous differential equation. The equation $\frac{d^2y}{dx^2} = 0$ characterizes the set of all straight lines because the rate of change of the slope is zero for any linear function.
Final Solution: $\frac{d^2y}{dx^2} = 0$
More Questions from Class 12 Mathematics Differential Equations EXERCISE 9.3
- Q1: Find the solution of $\frac{dy}{dx} = \frac{2y}{x}$.
- Q3: Given that $\frac{dy}{dx} = e^{-2y}$ and $y = 0$ when $x = 5$. Find the value of $x$ when $y = 3$.
- Q4: Solve the differential equation $(x^2 – 1) \frac{dy}{dx} + 2xy = \frac{1}{x^2 - 1}$.
- Q5: Solve the differential equation $\frac{dy}{dx} + 2xy = y^2$.
- Q6: Find the general solution of $\frac{dy}{dx} + ay = e^{mx}$.
- Q7: Solve the differential equation $\frac{dy}{dx} + 1 = e^{x+y}$.
- Q8: Solve: $ydx – xdy = x^2ydx$.
- Q9: Solve the differential equation $\frac{dy}{dx} = 1 + x + y^2 + xy^2$, when $y = 0$, $x = 0$.
- Q10: Find the general solution of $(x + 2y^3)\frac{dy}{dx} = y$.
- Q11: If $y(x)$ is a solution of $\frac{dy}{dx} + \frac{2x}{1+x^2}y = \frac{1}{(1+x^2)^2}$ and $y (0) = 1$, then find the value of $y(\frac{\pi}{2})$.
- Q12: If $y(t)$ is a solution of $(1 + t)\frac{dy}{dt} – ty = 1$ and $y (0) = – 1$, then show that $y (1) = –\frac{1}{2}$.
- Q13: Form the differential equation having $y = (\sin^{-1}x)^2 + A\cos^{-1}x + B$, where $A$ and $B$ are arbitrary constants, as its general solution.
- Q14: Form the differential equation of all circles which pass through origin and whose centres lie on y-axis.
- Q15: Find the equation of a curve passing through origin and satisfying the differential equation $(1+x^2)\frac{dy}{dx} + 2xy = 4x^2$.
- Q16: Solve : $x^2\frac{dy}{dx} = x^2 + xy + y^2$.
- Q17: Find the general solution of the differential equation $(1 + y^2) + (x – e^{\tan^{-1}y})\frac{dy}{dx} = 0$.
- Q18: Find the general solution of $y^2dx + (x^2 – xy + y^2) dy = 0$.
- Q19: Solve : $(x + y) (dx – dy) = dx + dy$.[Hint: Substitute $x + y = z$ after seperating $dx$ and $dy$]
- Q20: Solve : $2 (y + 3) – xy\frac{dy}{dx} = 0$, given that $y (1) = – 2$.
- Q21: Solve the differential equation $dy = \cos x (2 – y \csc x) dx$ given that $y = 2$ when $x = \frac{\pi}{2}$.
- Q22: Form the differential equation by eliminating $A$ and $B$ in $Ax^2 + By^2 = 1$.
- Q23: Solve the differential equation $(1 + y^2) \tan^{-1}x dx + 2y (1 + x^2) dy = 0$.
- Q24: Find the differential equation of system of concentric circles with centre (1, 2).
- Q25: Solve : $\frac{d}{dx}(y + xy) = x (\sin x + \log x)$
- Q26: Find the general solution of $(1 + \tan y) (dx – dy) + 2xdy = 0$.
- Q27: Solve : $\frac{dy}{dx} = \cos(x + y) + \sin (x + y)$.[Hint: Substitute $x + y = z$]
- Q28: Find the general solution of $\frac{dy}{dx} - 3y = \sin 2x$.
- Q29: Find the equation of a curve passing through (2, 1) if the slope of the tangent to the curve at any point $(x, y)$ is $\frac{x^2 + y^2}{2xy}$.
- Q30: Find the equation of the curve through the point (1, 0) if the slope of the tangent to the curve at any point $(x, y)$ is $\frac{y-1}{x^2+x}$.
- Q31: Find the equation of a curve passing through origin if the slope of the tangent to the curve at any point $(x, y)$ is equal to the square of the difference of the abcissa and ordinate of the point.
- Q32: Find the equation of a curve passing through the point (1, 1). If the tangent drawn at any point P $(x, y)$ on the curve meets the co-ordinate axes at A and B such that P is the mid-point of AB.
- Q33: Solve : $x\frac{dy}{dx} = y (\log y – \log x + 1)$
- Q34: The degree of the differential equation $(\frac{d^2y}{dx^2})^2 + (\frac{dy}{dx})^2 = x \sin(\frac{dy}{dx})$ is:
- Q35: The degree of the differential equation $[1 + (\frac{dy}{dx})^2]^{\frac{3}{2}} = \frac{d^2y}{dx^2}$ is
- Q36: The order and degree of the differential equation $(\frac{d^2y}{dx^2})^{\frac{1}{2}} + (\frac{dy}{dx})^{\frac{1}{5}} + 4 = 0$, respectively, are
- Q37: If $y = e^{-x} (A\cos x + B\sin x)$, then $y$ is a solution of
- Q38: The differential equation for $y = A\cos \alpha x + B\sin \alpha x$, where $A$ and $B$ are arbitrary constants is
- Q39: Solution of differential equation $xdy – ydx = 0$ represents :
- Q40: Integrating factor of the differential equation $\cos x \frac{dy}{dx} + y\sin x = 1$ is :
- Q41: Solution of the differential equation $\tan y \sec^2x dx + \tan x \sec^2y dy = 0$ is :
- Q42: Family $y = Ax + A^3$ of curves is represented by the differential equation of degree :
- Q43: Integrating factor of $x\frac{dy}{dx} – y = x^4 – 3x$ is :
- Q44: Solution of $\frac{dy}{dx} - y = 1$, $y (0) = 1$ is given by
- Q45: The number of solutions of $\frac{dy}{dx} = \frac{y+1}{x-1}$ when $y (1) = 2$ is :
- Q46: Which of the following is a second order differential equation?
- Q47: Integrating factor of the differential equation $(1 – x^2)\frac{dy}{dx} - xy = 1$ is
- Q48: $\tan^{-1} x + \tan^{-1} y = c$ is the general solution of the differential equation:
- Q49: The differential equation $y\frac{dy}{dx} + x = c$ represents :
- Q50: The general solution of $e^x \cos y dx – e^x \sin y dy = 0$ is :
- Q51: The degree of the differential equation $(\frac{d^2y}{dx^2})^2 + (\frac{dy}{dx})^3 + y^5 + 6 = 0$ is :
- Q52: The solution of $\frac{dy}{dx} + y = e^{-x}, y(0) = 0$ is :
- Q53: Integrating factor of the differential equation $\frac{dy}{dx} + y \tan x - \sec x = 0$ is:
- Q54: The solution of the differential equation $\frac{dy}{dx} = \frac{1+y^2}{1+x^2}$ is:
- Q55: The integrating factor of the differential equation $\frac{dy}{dx} + (1+\frac{1}{x})y = ...$ is:
- Q56: $y = ae^{mx} + be^{-mx}$ satisfies which of the following differential equation?
- Q57: The solution of the differential equation $\cos x \sin y dx + \sin x \cos y dy = 0$ is :
- Q58: The solution of $\frac{dy}{dx} + \frac{y}{x} = e^x$ is:
- Q59: The differential equation of the family of curves $x^2 + y^2 – 2ay = 0$, where $a$ is arbitrary constant, is:
- Q60: Family $y = Ax + A^3$ of curves will correspond to a differential equation of order
- Q61: The general solution of $\frac{dy}{dx} = e^{y-2x}$ is :
- Q62: The curve for which the slope of the tangent at any point is equal to the ratio of the abcissa to the ordinate of the point is :
- Q63: The general solution of the differential equation $\frac{dy}{dx} = e^{x^2} + 2xy$ is :
- Q64: The solution of the equation $(2y – 1) dx – (2x + 3)dy = 0$ is :
- Q65: The differential equation for which $y = a\cos x + b\sin x$ is a solution, is :
- Q66: The solution of $\frac{dy}{dx} + y = e^{-x}, y (0) = 0$ is :
- Q67: The order and degree of the differential equation $(\frac{d^3y}{dx^3})^2 - 3(\frac{d^2y}{dx^2}) + 2(\frac{dy}{dx})^4 = y$ are :
- Q68: The order and degree of the differential equation $[1 + (\frac{dy}{dx})^2]^{\frac{3}{2}} = \frac{d^2y}{dx^2}$ are :
- Q69: The differential equation of the family of curves $y^2 = 4a (x + a)$ is :
- Q70: Which of the following is the general solution of $\frac{d^2y}{dx^2} - 2\frac{dy}{dx} + 2y = 0$ ?
- Q71: General solution of $\frac{dy}{dx} + y \tan x = \sec x$ is :
- Q72: Solution of the differential equation $\frac{dy}{dx} + \frac{y}{x} = \sin x$ is :
- Q73: The general solution of the differential equation $(e^x + 1) ydy = (y + 1) e^x dx$ is:
- Q74: The solution of the differential equation $\frac{dy}{dx} = e^{x-y} + x^2 e^{-y}$ is :
- Q75: The solution of the differential equation $\frac{dy}{dx} + \frac{2xy}{1+x^2} = \frac{1}{(1+x^2)^2}$ is :
- Q76(i): Fill in the blanks: The degree of the differential equation $\frac{d^2y}{dx^2} + e^{\frac{dy}{dx}} = 0$ is _________.
- Q76(ii): Fill in the blanks: The degree of the differential equation $\sqrt{1 + (\frac{dy}{dx})^2} = x$ is _________.
- Q76(iii): Fill in the blanks: The number of arbitrary constants in the general solution of a differential equation of order three is _________.
- Q76(iv): Fill in the blanks: $\frac{dy}{dx} + \frac{y}{x\log x} = \frac{1}{x}$ is an equation of the type _________.
- Q76(ix): Fill in the blanks: General solution of $\frac{dy}{dx} + \frac{y}{x} = \sin x$ is _________.
- Q76(v): Fill in the blanks: General solution of the differential equation of the type $\frac{dx}{dy} + P_1 x = Q_1$ is given by _________.
- Q76(vi): Fill in the blanks: The solution of the differential equation $x\frac{dy}{dx} + 2y = x^2$ is _________.
- Q76(vii): Fill in the blanks: The solution of $(1 + x^2) \frac{dy}{dx} +2xy – 4x^2 = 0$ is _________.
- Q76(viii): Fill in the blanks: The solution of the differential equation $ydx + (x + xy)dy = 0$ is ______.
- Q76(x): Fill in the blanks: The solution of differential equation $\cot y dx = xdy$ is _________.
- Q76(xi): Fill in the blanks: The integrating factor of $\frac{dy}{dx} + \frac{y}{x(y+1)} = 1$ is _________.
- Q77(i): State True or False: Integrating factor of the differential of the form $\frac{dx}{dy} + p_1 x = Q_1$ is given by $e^{\int p_1 dy}$.
- Q77(ii): State True or False: Solution of the differential equation of the type $\frac{dx}{dy} + p_1 x = Q_1$ is given by $x \cdot I.F. = \int (Q_1 \times I.F.) dy$.
- Q77(iii): State True or False: Correct substitution for the solution of the differential equation of the type $\frac{dy}{dx} = f(x, y)$, where $f (x, y)$ is a homogeneous function of zero degree is $y = vx$.
- Q77(iv): State True or False: Correct substitution for the solution of the differential equation of the type $\frac{dx}{dy} = g(x, y)$ where $g(x, y)$ is a homogeneous function of the degree zero is $x = vy$.
- Q77(ix): State True or False: The solution of the differential equation $\frac{dy}{dx} = \frac{x+2y}{x}$ is $x + y = kx^2$.
- Q77(v): State True or False: Number of arbitrary constants in the particular solution of a differential equation of order two is two.
- Q77(vi): State True or False: The differential equation representing the family of circles $x^2 + (y – a)^2 = a^2$ will be of order two.
- Q77(vii): State True or False: The solution of $\frac{dy}{dx} = (\frac{y}{x})^{\frac{1}{3}}$ is $y^{\frac{2}{3}} – x^{\frac{2}{3}} = c$.
- Q77(viii): State True or False: Differential equation representing the family of curves $y = e^x (A\cos x + B\sin x)$ is $\frac{d^2y}{dx^2} – 2\frac{dy}{dx} + 2y = 0$.
- Q77(x): State True or False: Solution of $\frac{dy}{dx} = \frac{y}{x} + \tan(\frac{y}{x})$ is $\sin(\frac{y}{x}) = cx$.
- Q77(xi): State True or False: The differential equation of all non horizontal lines in a plane is $\frac{d^2x}{dy^2} = 0$.
CBSE Solutions for Class 12 Mathematics Differential Equations
Chapters in CBSE - Class 12 Mathematics
Top Tutors who teach Differential Equations
I am the author of seven books and a proud recipient of the Best Teacher Award from a reputed CBSE school. With over eight years of teaching experience at the school level and fifteen years of expertise in teaching Communication Skills and English Literature at a prestigious university, I bring a strong academic foundation and practical understanding of student development. My diverse teaching background has enabled me to mentor learners with varying abilities, helping them grow intellectually, linguistically, and personally. With this rich experience, I strive to ensure the all-around development of every student, fostering confidence, clarity of thought, and a lasting appreciation for the English language.
I am an experienced, qualified teacher with over 9 years of experience in teaching Math across different boards including CBSE, ICSE and IGCSE and state board 9-12 and IIT JEE engineering entrance mathematics . I have worked in reputed institutes like Vibrant academy, Resonance in Kota and in Byjus and Modi School in Rajkot. Passionate about solving mathematical problems. And I have also been carrying out year of experience in Engineering Mathematics.
Eti mam is a good teacher. She have a different way of teaching. I am glad to improved grades of my son.
Physics is not about just getting answer of a problem, it is to visualize , Join me and experience this. Beside your topmost result i will make it a fun you will really enjoy it. My basic way of teaching is from day to day life. I am skillful in using modern day technology and software in constructive way.
Really great physics teacher. The way he explains concepts makes them easy to understand, and he goes into enough detail to make sure you truly get the topic. Physics feels much less intimidating and a lot more interesting because of his teaching.
I'm a mathematics' teacher. My goal is to teach you how you can think out a solution rather than roboting your way out. We will dive deep into concepts of mathematics and come out as a well learned and scrupulous student. I am ready to clear your hurdles with most accurate way. I have taught at many academies for JEE preparations. In addition to it I have taught online in UrbanPro from past 4 years.
Suman is an awesome teacher and connects well with the student and gets them to grasp concepts and be interested in the subject. Highly recommend him for math.
I have 21 years of experience in teaching chemistry and training the students for both board and competitive exams.
Fantastic teacher with great experience in her field. Definitely impressed. Best for organic chemistry.
Other Subjects in CBSE - Class 12
Download free CBSE - Class 12 Mathematics Differential Equations EXERCISE 9.3 worksheets
Download Now