Maths Questions

Find the angle between the curves xy = 6 and \(x^2 y\) =12.

Solution : The equation of the two curves are xy = 6ย  ย  ย  ย  ย  โ€ฆโ€ฆ.(i) and, \(x^2 y\) = 12ย  ย  ย  ย  ย  ย  โ€ฆโ€ฆโ€ฆโ€ฆ(ii) from (i) , we obtain y = \(6\over x\). Putting this value of y in (ii), we obtain \(x^2\) \((6\over x)\) = 12 \(\implies\) 6x = 12 โ€ฆ

Find the angle between the curves xy = 6 and \(x^2 y\) =12. Read More ยป

Check the orthogonality of the curves \(y^2\) = x and \(x^2\) = y.

Solution : Solving the curves simultaneously we get points of intersection as (1, 1) and (0, 0). At (1, 1) for first curve \(2y({dy\over dx})_1\) = 1ย  \(\implies\)ย  \(m_1\) = \(1\over 2\) & for second curve 2x = \(({dy\over dx})_2\) \(\implies\)ย  \(m_2\) = 2 \(m_1m_2\) = -1 at (1, 1). But at (0, 0) clearly โ€ฆ

Check the orthogonality of the curves \(y^2\) = x and \(x^2\) = y. Read More ยป

The angle of intersection between the curve \(x^2\) = 32y and \(y^2\) = 4x at point (16, 8) is

Solution : \(x^2\) = 32yย  \(\implies\)ย  \(dy\over dx\) = \(x\over 16\)ย  \(\implies\)ย  \(y^2\) = 4x \(\implies\)ย  \(dy\over dx\) = \(2\over y\) \(\therefore\)ย  atย  (16, 8), \((dy\over dx)_1\) = 1, \((dy\over dx)_2\) = \(1\over 4\) So, required angle = \(tan^{-1}({1 โ€“ {1\over 4}\over 1 + 1({1\over 4})})\) = \(tan^{-1}({3\over 5})\) Similar Questions Find the equations of โ€ฆ

The angle of intersection between the curve \(x^2\) = 32y and \(y^2\) = 4x at point (16, 8) is Read More ยป

Find the interval in which f(x) = \(-x^2 โ€“ 2x + 15\) is increasing or decreasing.

Solution : We have,ย  f(x) = \(-x^2 โ€“ 2x + 15\) \(\implies\) f'(x) = -2x โ€“ 2 = -2(x + 1) for f(x) to be increasing, we must have f'(x) > 0 -2(x + 1) > 0 \(\implies\) x + 1 < 0 \(\implies\) x < -1 \(\implies\) x \(\in\) \((-\infty, -1)\). Thus f(x) is โ€ฆ

Find the interval in which f(x) = \(-x^2 โ€“ 2x + 15\) is increasing or decreasing. Read More ยป

Prove that \(f(\theta)\) = \({4sin \theta\over 2 + cos\theta} โ€“ \theta\) is an increasing function of \(\theta\) in \([0, {\pi\over 2}]\).

Solution : We have, \(f(\theta)\) = \({4sin \theta\over 2 + cos\theta} โ€“ \theta\) \(\implies\) \(f'(\theta)\) = \((2 + cos\theta)(4 cos\theta) + 4 sin^2\theta\over (2 + cos\theta)^2\) โ€“ 1 \(\implies\) \(f'(\theta)\)ย  = \(8 cos\theta + 4\over (2 + cos\theta)^2\) โ€“ 1 \(\implies\) \(f'(\theta)\) = \(4\cos\theta โ€“ cos^2\theta\over (2 + cos\theta)^2\) \(\implies\) \(f'(\theta)\) = \(cos\theta(4 โ€“ cos\theta)\over โ€ฆ

Prove that \(f(\theta)\) = \({4sin \theta\over 2 + cos\theta} โ€“ \theta\) is an increasing function of \(\theta\) in \([0, {\pi\over 2}]\). Read More ยป

Prove that the function f(x) = \(x^3 โ€“ 3x^2 + 3x โ€“ 100\) is increasing on R

Solution : We have, f(x) = \(x^3 โ€“ 3x^2 + 3x โ€“ 100\) \(\implies\)ย  f'(x) = \(3x^2 โ€“ 6x + 3\) = \(3(x โ€“ 1)^2\) Now, x \(\in\) R \(\implies\)ย  \((x โ€“ 1)^2\)ย  \(\ge\)ย  0ย  \(\implies\)ย  f'(x)ย  \(\ge\) 0. Thus, f'(x) \(\ge\) 0 for all x \(\in\) R. Hence, f(x) is increasing on R. Similar โ€ฆ

Prove that the function f(x) = \(x^3 โ€“ 3x^2 + 3x โ€“ 100\) is increasing on R Read More ยป

Separate \([0, {\pi\over 2}]\) into subintervals in which f(x) = sin 3x is increasing or decreasing.

Solution : We have, f(x) = sin 3x \(\therefore\)ย  ย f'(x) = 3cos 3x Now,ย  0 < x < \(pi\over 2\)ย  ย \(\implies\)ย  0 < 3x < \(3\pi\over 2\) Since cosine function is positive in first quadrant and negative in the second and third quadrants. Therefore, we consider the following cases. Case 1 : When 0 < โ€ฆ

Separate \([0, {\pi\over 2}]\) into subintervals in which f(x) = sin 3x is increasing or decreasing. Read More ยป

Find the point of inflection for f(x) = \(x^4\over 12\) โ€“ \(5x^3\over 6\) + \(3x^2\) + 7.

Solution : f(x) = \(x^4\over 12\) โ€“ \(5x^3\over 6\) + \(3x^2\) + 7. f'(x) = \(x^3\over 3\) โ€“ \(5x^2\over 2\) + 6x fโ€(x) = \(x^2\) โ€“ 5x + 6 Since, fโ€(x) = 0 at point of inflection. \(\implies\) \(x^2\) โ€“ 5x + 6 = 0 \(\implies\) x = 2 and x = 3 Hence, points โ€ฆ

Find the point of inflection for f(x) = \(x^4\over 12\) โ€“ \(5x^3\over 6\) + \(3x^2\) + 7. Read More ยป

Find the point of inflection for the curve y = \(x^3 โ€“ 6x^2 + 12x + 5\).

Solution : y = \(x^3 โ€“ 6x^2 + 12x + 5\) yโ€™ = \(3x^2 โ€“ 12x + 12\) yโ€ = \(6x โ€“ 12\) yโ€ = 0 \(\implies\) 6x โ€“ 12 = 0 \(\implies\)ย  x = 2 Since, yโ€ = 0 at x = 2, Hence the point of inflection is 2. Similar Questions Prove that โ€ฆ

Find the point of inflection for the curve y = \(x^3 โ€“ 6x^2 + 12x + 5\). Read More ยป

Find the inflection point of f(x) = \(3x^4 โ€“ 4x^3\).

Solution : f(x) = \(3x^4 โ€“ 4x^3\) f'(x) = \(12x^3 โ€“ 12x^2\) f'(x) = \(12x^2(x โ€“ 1)\) Now, fโ€(x) = \(12(3x^2 โ€“ 2x)\) fโ€(x) = 12x(3x โ€“ 2) fโ€(x) = 0ย  \(\implies\)ย  x = 0, 2/3 Here, fโ€(x) = 0 Thus, x = 0, 2/3 are the inflection points. Similar Questions Prove that the function โ€ฆ

Find the inflection point of f(x) = \(3x^4 โ€“ 4x^3\). Read More ยป

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