1. Given the differential equation: dy/dx + P y = Q The integrating factor μ(x) is defined by: μ(x) = exp(∫ P dx) We are told that: μ(x) = cos²x Taking the natural logarithm of both sides: ln μ(x) = ln(cos²x) = 2 ln|cos x| Differentiate with respect to x: d/dx [ln μ(x)] = d/dx [2 ln|cos x|] = 2 · (−tanRead more

    Given the differential equation:
    dy/dx + P y = Q

    The integrating factor μ(x) is defined by:
    μ(x) = exp(∫ P dx)

    We are told that:
    μ(x) = cos²x

    Taking the natural logarithm of both sides:
    ln μ(x) = ln(cos²x) = 2 ln|cos x|

    Differentiate with respect to x:
    d/dx [ln μ(x)] = d/dx [2 ln|cos x|] = 2 · (−tan x) = −2 tan x

    But we also have:
    d/dx [ln μ(x)] = P

    Thus, we find:
    P = −2 tan x

    Therefore, the correct answer is:
    −2 tan x

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  2. The family of parabolas with axes parallel to the y-axis can be expressed as: y = a x² + b x + c which contains three arbitrary constants, all of them, namely a, b, and c. A differential equation must therefore have a general solution containing three arbitrary constants. Three successive differentiRead more

    The family of parabolas with axes parallel to the y-axis can be expressed as:
    y = a x² + b x + c
    which contains three arbitrary constants, all of them, namely a, b, and c.

    A differential equation must therefore have a general solution containing three arbitrary constants. Three successive differentiations eliminate all the arbitrary constants. Indeed three successive differentiations of:
    y = a x² + b x + c
    After this gives:
    y′ = 2a x + b
    which twice gives:
    y″ = 2a
    and thrice gives:
    y‴ = 0
     
    So the differential equation that represents the family is:
    y‴ = 0
     
    This is a third order differential equation.
     
    Thus, the order of the differential equation is 3.

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  3. The area bounded by the curve y = cos x, the x-axis, and the given ordinates x = π/2 and x = π is given by the definite integral: A = ∫[π/2 to π] cos x dx Evaluating the integral: ∫ cos x dx = sin x Applying the limits: A = sin(π) - sin(π/2) = 0 - 1 = -1 Since area cannot be negative, we take the abRead more

    The area bounded by the curve y = cos x, the x-axis, and the given ordinates x = π/2 and x = π is given by the definite integral:

    A = ∫[π/2 to π] cos x dx

    Evaluating the integral:
    ∫ cos x dx = sin x

    Applying the limits:
    A = sin(π) – sin(π/2)
    = 0 – 1
    = -1

    Since area cannot be negative, we take the absolute value:
    A = 1 square unit

    Thus, the correct answer is: 1 sq. unit

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  4. We are given that A is a square matrix of order 3 and |A| = -4. We are asked to find the value of |adj(A)|. The formula for the determinant of the adjugate matrix adj(A) for a square matrix A of order n is |adj(A)| = |A|^(n-1) For a matrix of order 3, n = 3. Hence, the above formula becomes |adj(A)|Read more

    We are given that A is a square matrix of order 3 and |A| = -4. We are asked to find the value of |adj(A)|.
    The formula for the determinant of the adjugate matrix adj(A) for a square matrix A of order n is
    |adj(A)| = |A|^(n-1)
    For a matrix of order 3, n = 3. Hence, the above formula becomes
    |adj(A)| = |A|^(3-1) = |A|²
    We know that |A| = -4. So,

    |adj(A)| = (-4)² = 16

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  5. The differential equation given is: sin(x) + cos(dy/dx) = y² To know the degree of the differential equation, we have the following steps: 1. Rearrange the formula: The formula contains dy/dx that is not raised to any power directly. However, with the term cos(dy/dx) the degree calculation is compliRead more

    The differential equation given is:

    sin(x) + cos(dy/dx) = y²

    To know the degree of the differential equation, we have the following steps:
    1. Rearrange the formula: The formula contains dy/dx that is not raised to any power directly. However, with the term cos(dy/dx) the degree calculation is complicated since it deals with a trigonometric function of the derivative.

    2. Degree of a differential equation: The degree of a differential equation is defined to be the highest power of the highest-order derivative after the equation has been made free from any irrational terms, fractional powers, or trigonometric functions involving derivatives.

    3. This equation contains a trigonometric function, cos(dy/dx), whose argument is a first derivative, not an algebraic expression, not a polynomial, not a simple rational term. Since it’s placed within the argument of a trigonometric function, the degree is undefined.

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