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int(1)/(sqrt(9-4x^(2)))dx

194x2dx \int \frac{1}{\sqrt{9-4 x^{2}}} d x

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Q. 194x2dx \int \frac{1}{\sqrt{9-4 x^{2}}} d x
  1. Recognize standard form: Recognize the integral as a standard form. The integral 194x2dx\int\frac{1}{\sqrt{9-4x^{2}}}\,dx resembles the integral of the form 1a2x2dx\int\frac{1}{\sqrt{a^{2} - x^{2}}}\,dx, which is a standard form for the inverse trigonometric function arcsin(xa)\arcsin(\frac{x}{a}).
  2. Identify a2a^2: Identify a2a^2 from the integral.\newlineIn our integral, a2=9a^2 = 9, so a=3a = 3. This means we can rewrite the integral in terms of a standard extarcsin ext{arcsin} function.
  3. Use substitution x=32sin(u)x=\frac{3}{2}\sin(u): Rewrite the integral using the substitution x=32sin(u)x = \frac{3}{2}\sin(u). Let x=32sin(u)x = \frac{3}{2}\sin(u), then dx=32cos(u)dudx = \frac{3}{2}\cos(u)du. We need to find the limits of integration in terms of uu, but since this is an indefinite integral, we will just perform the substitution.
  4. Substitute xx and dxdx: Substitute xx and dxdx in the integral.\newlineSubstituting xx and dxdx into the integral, we get 194(32sin(u))2(32)cos(u)du\int \frac{1}{\sqrt{9-4\left(\frac{3}{2}\sin(u)\right)^2}} \cdot \left(\frac{3}{2}\right)\cos(u)\,du.
  5. Simplify expression: Simplify the integral.\newlineSimplify the expression under the square root: 94(32)2sin2(u)=99sin2(u)=9(1sin2(u))=9cos2(u)9 - 4\left(\frac{3}{2}\right)^2\sin^2(u) = 9 - 9\sin^2(u) = 9(1 - \sin^2(u)) = 9\cos^2(u).\newlineThe integral becomes 19cos2(u)(32)cos(u)du\int \frac{1}{\sqrt{9\cos^2(u)}} \cdot \left(\frac{3}{2}\right)\cos(u)\,du.
  6. Further simplify integral: Further simplify the integral.\newlineSince 9cos2(u)=3cos(u)\sqrt{9\cos^2(u)} = 3\cos(u), the integral simplifies to 13cos(u)(32)cos(u)du=12du\int\frac{1}{3\cos(u)} \cdot \left(\frac{3}{2}\right)\cos(u)\,du = \int\frac{1}{2}\,du.
  7. Integrate with respect to uu: Integrate with respect to uu. The integral of 12\frac{1}{2} with respect to uu is (12)u+C\left(\frac{1}{2}\right)u + C.
  8. Substitute back for u: Substitute back for u.\newlineWe need to express our answer in terms of xx, so we substitute back using the original substitution x=32sin(u)x = \frac{3}{2}\sin(u). We solve for uu: sin(u)=23x\sin(u) = \frac{2}{3}x, so u=arcsin(23x)u = \arcsin(\frac{2}{3}x).
  9. Write final answer: Write the final answer.\newlineThe final answer is (12)arcsin(23x)+C(\frac{1}{2})\arcsin(\frac{2}{3}x) + C.

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