Maths-
General
Easy

Question

If length of focal chord of y2 = 4ax is λ, then angle between axis of parabola and focal chord is

  1. ± sin–1 square root of fraction numerator 2 a over denominator l end fraction end root    
  2. ± sin–1 square root of fraction numerator 4 a over denominator l end fraction end root    
  3. ± tan–1 square root of fraction numerator 4 a over denominator l end fraction end root    
  4. None of these    

The correct answer is: ± sin–1 square root of fraction numerator 4 a over denominator l end fraction end root


    Let any point on focal chord is P(h, k)

    where h = a + r cos proportional to
    k = r sin proportional to
    therefore Put (h, k) in y2 = 4ax
    rightwards double arrow r2 sin2  = 4a (a + r cos proportional to)
    therefore blankr1 + r2 =fraction numerator 4 a cos invisible function application alpha over denominator sin to the power of 2 end exponent invisible function application alpha end fraction, r1r2 = fraction numerator negative 4 a to the power of 2 end exponent over denominator sin to the power of 2 end exponent invisible function application alpha end fraction
    Now here length of focal chord is
    l= |r1| + |r2|
    = r1 –r2
    = square root of left parenthesis r subscript 1 end subscript plus r subscript 2 end subscript right parenthesis to the power of 2 end exponent minus 4 r subscript 1 end subscript r subscript 2 end subscript end root
    thereforeproportional tol = 4a/sin2 proportional to       

    Related Questions to study

    General
    maths-

    Assertion: If a > 0 and b2 – 4ac < 0 then the value of the integral not stretchy integral fraction numerator d x over denominator a x to the power of 2 end exponent plus b x plus c end fraction will be of the type mutan–1 fraction numerator x plus A over denominator B end fraction + C, where A, B, C, mu are constants.
    Reason: If a > 0, b2 – 4ac < 0 then ax2 + b x + c can be written as sum of two squares.

    Assertion: If a > 0 and b2 – 4ac < 0 then the value of the integral not stretchy integral fraction numerator d x over denominator a x to the power of 2 end exponent plus b x plus c end fraction will be of the type mutan–1 fraction numerator x plus A over denominator B end fraction + C, where A, B, C, mu are constants.
    Reason: If a > 0, b2 – 4ac < 0 then ax2 + b x + c can be written as sum of two squares.

    maths-General
    General
    physics-

    The diagram below shows the propagation of a wave. Which points are in same phase

    The diagram below shows the propagation of a wave. Which points are in same phase

    physics-General
    General
    maths-

    If f(x) is the primitive of fraction numerator sin invisible function application root index 3 of x end root log invisible function application left parenthesis 1 plus 3 x right parenthesis over denominator left parenthesis tan to the power of – 1 end exponent invisible function application square root of x right parenthesis to the power of 2 end exponent left parenthesis e to the power of root index 3 of x end root end exponent – 1 right parenthesis end fraction (x not equal to 0), then stack l i m with x rightwards arrow 0 below f ' (x) is -

    If f(x) is the primitive of fraction numerator sin invisible function application root index 3 of x end root log invisible function application left parenthesis 1 plus 3 x right parenthesis over denominator left parenthesis tan to the power of – 1 end exponent invisible function application square root of x right parenthesis to the power of 2 end exponent left parenthesis e to the power of root index 3 of x end root end exponent – 1 right parenthesis end fraction (x not equal to 0), then stack l i m with x rightwards arrow 0 below f ' (x) is -

    maths-General
    parallel
    General
    maths-

    The value of lambda for which not stretchy integral fraction numerator 4 x to the power of 3 end exponent plus lambda 4 to the power of x end exponent over denominator 4 to the power of x end exponent plus x to the power of 4 end exponent end fraction dx = log (4x + x4) is -

    The value of lambda for which not stretchy integral fraction numerator 4 x to the power of 3 end exponent plus lambda 4 to the power of x end exponent over denominator 4 to the power of x end exponent plus x to the power of 4 end exponent end fraction dx = log (4x + x4) is -

    maths-General
    General
    Maths-

    not stretchy integral fraction numerator cos invisible function application 2 x minus cos invisible function application 2 theta over denominator cos invisible function application x minus cos invisible function application theta end fractiondx =

    not stretchy integral fraction numerator cos invisible function application 2 x minus cos invisible function application 2 theta over denominator cos invisible function application x minus cos invisible function application theta end fractiondx =

    Maths-General
    General
    maths-

    If f(x) is the primitive of fraction numerator sin invisible function application root index 3 of x end root log invisible function application left parenthesis 1 plus 3 x right parenthesis over denominator left parenthesis tan to the power of negative 1 end exponent invisible function application square root of x right parenthesis to the power of 2 end exponent left parenthesis e to the power of root index 3 of x end root end exponent minus 1 right parenthesis end fraction(x not equal to 0), then stack l i m with x rightwards arrow 0 below f ´ left parenthesis x right parenthesis is-

    If f(x) is the primitive of fraction numerator sin invisible function application root index 3 of x end root log invisible function application left parenthesis 1 plus 3 x right parenthesis over denominator left parenthesis tan to the power of negative 1 end exponent invisible function application square root of x right parenthesis to the power of 2 end exponent left parenthesis e to the power of root index 3 of x end root end exponent minus 1 right parenthesis end fraction(x not equal to 0), then stack l i m with x rightwards arrow 0 below f ´ left parenthesis x right parenthesis is-

    maths-General
    parallel
    General
    maths-

    Let the line l x+ my = 1 cut the parabola y2 = 4ax in the points A and B. Normals at A and B meet at point C. Normal from C other than these two meet the parabola at D then the coordinate of D are

    Let the line l x+ my = 1 cut the parabola y2 = 4ax in the points A and B. Normals at A and B meet at point C. Normal from C other than these two meet the parabola at D then the coordinate of D are

    maths-General
    General
    maths-

    A line bisecting the ordinate PN of a point P (at2, 2at), t > 0, on the parabola y2 = 4ax is drawn parallel to the axis to meet the curve at Q. If NQ meets the tangent at the vertex at the point T, Then the coordinates of T are.

    A line bisecting the ordinate PN of a point P (at2, 2at), t > 0, on the parabola y2 = 4ax is drawn parallel to the axis to meet the curve at Q. If NQ meets the tangent at the vertex at the point T, Then the coordinates of T are.

    maths-General
    General
    maths-

    If the tangent at the point P(x1, y1) to the parabola y2 = 4ax meets the parabola y2 = 4a(x + b) at Q and R, then the mid-point of QR is -

    If the tangent at the point P(x1, y1) to the parabola y2 = 4ax meets the parabola y2 = 4a(x + b) at Q and R, then the mid-point of QR is -

    maths-General
    parallel
    General
    maths-

    Condition on 'a' and 'b', such that a point can be found so that two tangents can be drawn from it to parabola S1 = 0 are normals to the parabola S2= 0 is-

    Condition on 'a' and 'b', such that a point can be found so that two tangents can be drawn from it to parabola S1 = 0 are normals to the parabola S2= 0 is-

    maths-General
    General
    maths-

    The normal y = mx – 2am – am2 to the parabola y2 = 4ax subtends a right angle at the origin, then-

    The normal y = mx – 2am – am2 to the parabola y2 = 4ax subtends a right angle at the origin, then-

    maths-General
    General
    maths-

    If the point (2a, a) lies inside the parabola x2 – 2x – 4y + 3 = 0, then a lies in the interval-

    If the point (2a, a) lies inside the parabola x2 – 2x – 4y + 3 = 0, then a lies in the interval-

    maths-General
    parallel
    General
    maths-

    The parametric equation of a parabola is x = 4t2, y = 8t. The tangents at the points whose parameters are fraction numerator 1 over denominator 2 end fraction and 1 meet on the line -

    The parametric equation of a parabola is x = 4t2, y = 8t. The tangents at the points whose parameters are fraction numerator 1 over denominator 2 end fraction and 1 meet on the line -

    maths-General
    General
    maths-

    Let F be the focus of the parabola y2 = 4ax and M be the foot of perpendicular from point P(at2, 2at) on the tangent at the vertex. If N is a point on the tangent at P then fraction numerator M N over denominator F N end fraction equals-

    Let F be the focus of the parabola y2 = 4ax and M be the foot of perpendicular from point P(at2, 2at) on the tangent at the vertex. If N is a point on the tangent at P then fraction numerator M N over denominator F N end fraction equals-

    maths-General
    General
    physics-

    The equation y equals 0.15 sin invisible function application 5 x cos invisible function application 300 t comma describes a stationary wave. The wavelength of the stationary wave is

    The equation y equals 0.15 sin invisible function application 5 x cos invisible function application 300 t comma describes a stationary wave. The wavelength of the stationary wave is

    physics-General
    parallel

    card img

    With Turito Academy.

    card img

    With Turito Foundation.

    card img

    Get an Expert Advice From Turito.

    Turito Academy

    card img

    With Turito Academy.

    Test Prep

    card img

    With Turito Foundation.