Maths Questions

What is the integration of tan inverse root x ?

Solution : Let I = \(\int\) \(tan^{-1}\sqrt{x}\).1 dx By Applying integration by parts, Taking \(tan^{-1}\sqrt{x}\) as first function and 1 as second function. Then I = \(tan^{-1}\sqrt{x}\) \(\int\) 1 dx – \(\int\) {\(d\over dx\)\(tan^{-1}\sqrt{x}\) \(\int\) 1 dx } dx I = x\(tan^{-1}\sqrt{x}\) – \(\int\) \(1\over 2(1+x)\sqrt{x}\) . x dx Let \(\sqrt{x}\) = t \(1\over 2\sqrt{x}\)

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What is the integration of x tan inverse x dx ?

Solution : Let I = \(\int\) x\(tan^{-1}x\) dx By using Integration by parts rule, Taking tan inverse x as first function and x as second function. Then, I = (\(tan^{-1}x\)) \(\int\) x dx – \(\int\){\({d\over dx}\)(\(tan^{-1}x\) \(\int\) x dx} dx I = (\(tan^{-1}x\))\(x^2\over 2\) – \(\int\)\({1\over 1 + x^2}\) \(\times\) \(x^2\over 2\) dx \(\implies\) I

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Find the vector equation of a line which passes through the point A (3, 4, -7) and B (1, -1, 6)

Solution : We know that the vector equation of line passing through two points with position vectors \(\vec{a}\) and \(\vec{b}\) is, \(\vec{r}\) = \(\lambda\) \((\vec{b} – \vec{a})\) Here \(\vec{a}\) = \(3\hat{i} + 4\hat{j} – 7\hat{k}\) and \(\vec{b}\) = \(\hat{i} – \hat{j} + 6\hat{k}\). So, the vector equation of the required line is \(\vec{r}\) = (\(3\hat{i}

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Find the angle between the vectors with the direction ratios proportional to 4, -3, 5 and 3, 4, 5.

Solution : We have, \(\vec{a}\) = \(4\hat{i} – 3\hat{j} + 5\hat{k}\) and \(\vec{b}\) = \(3\hat{i} + 4\hat{j} + 5\hat{k}\) Let \(\theta\) is the angle between the given vectors. Then, cos\(\theta\) = \(\vec{a}.\vec{b}\over |\vec{a}||\vec{b}|\) \(\implies\) cos\(\theta\) = \(12 – 12 + 25\over \sqrt{16 + 9 + 25} \sqrt{16 + 9 + 25}\) = \(1\over 2\) \(\implies\)

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Find dot product of vectors \(\vec{a}\) = \(2\hat{i}+2\hat{j}-\hat{k}\) and \(\vec{b}\) = \(6\hat{i}-3\hat{j}+2\hat{k}\)

Solution : We have \(\vec{a}\) = \(2\hat{i}+2\hat{j}-\hat{k}\) and \(\vec{b}\) = \(6\hat{i}-3\hat{j}+2\hat{k}\) \(\vec{a}\).\(\vec{b}\) = (\(2\hat{i}+2\hat{j}-\hat{k}\)).(\(6\hat{i}-3\hat{j}+2\hat{k}\)) = (2)(6) + (2)(-3) + (-1)(2) = 12 – 6 – 2 = 4 Similar Questions Find the angle between the vectors with the direction ratios proportional to 4, -3, 5 and 3, 4, 5. Find the vector equation of a

Find dot product of vectors \(\vec{a}\) = \(2\hat{i}+2\hat{j}-\hat{k}\) and \(\vec{b}\) = \(6\hat{i}-3\hat{j}+2\hat{k}\) Read More »

Find the maximum value of 1 + \(sin({\pi\over 4} + \theta)\) + \(2cos({\pi\over 4} – \theta)\)

Solution : We have 1 + \(sin({\pi\over 4} + \theta)\) + \(2cos({\pi\over 4} – \theta)\) = 1 + \(1\over sqrt{2}\)\((cos\theta + cos\theta)\) + \(\sqrt{2}\)\((cos\theta + cos\theta)\) = 1 + \(({1\over \sqrt{2}} + \sqrt{2})\) + \((cos\theta + cos\theta)\) = 1 + \(({1\over \sqrt{2}} + \sqrt{2})\).\(\sqrt{2}cos(\theta – {pi\over 4})\) \(\therefore\)   Maximum Value = 1 + \(({1\over \sqrt{2}}

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Find the number of solutions of tanx + secx = 2cosx in [0, \(2\pi\)].

Solution : Here, tanx + secx = 2cosx       \(\implies\)     sinx + 1 = \(2cos^2x\) \(\implies\) \(2sin^2x\) + sinx – 1 = 0     \(\implies\)    sinx = \(1\over 2\), -1 But sinx = -1 \(\implies\) x = \(3\pi\over 2\) for which tanx + secx = 2cosx  is not defined. Thus, sinx =

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If \({1\over 6}sin\theta\), \(cos\theta\) and \(tan\theta\) are in G.P. then the general solution for \(\theta\) is

Solution : Since, \({1\over 6}sin\theta\), \(cos\theta\) and \(tan\theta\) are in G.P. \(\implies\) \(cos^2\theta\) = \({1\over 6}sin\theta\).\(cos\theta\) \(\implies\) \(6cos^3\theta\) + \(cos^2\theta\) – 1 = 0 \(\therefore\)   (\(2cos\theta – 1\))(\(3cos^2\theta\) + \(2cos\theta\) + 1) = 0 \(cos\theta\) = \(1\over 2\)       (other values are imaginary) \(cos\theta\) = \(cos\pi\over 3\)   \(\theta\) = \(2n\pi \pm {\pi\over 3}\),  n

If \({1\over 6}sin\theta\), \(cos\theta\) and \(tan\theta\) are in G.P. then the general solution for \(\theta\) is Read More »