Sheridan College · MATH15121D

Sheridan MATH15121D tutoring

Help with series, multivariable calculus and vector calculus in Sheridan MATH15121D.

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Course overview

MATH15121D extends Sheridan’s engineering-degree calculus at Davis Campus in Brampton to series, several variables and vector fields. Its scope includes partial derivatives, multiple integrals and line and surface integrals. Organize your work around the mathematical object: a series needs a convergence argument, a region needs bounds, and an oriented surface needs a consistent normal.

MATH15121D topics to review

Convergence, power series and Taylor expansionsPartial derivatives, gradients and constrained extremaMultiple integrals, coordinates and JacobiansLine integrals, surface flux and vector-calculus theorems

Common difficulties

  • Using a convergence test without checking its hypotheses or endpoints
  • Mixing a unit normal with the wrong surface-area element

Preparing for this course

Review single-variable integration, vectors and dot products. Draw the integration region before choosing bounds. Keep a small checklist for each coordinate change: transformed integrand, transformed region and Jacobian. For flux, label the required direction before computing any normal.

Registration requirements

The guidance above is study preparation, not an eligibility decision. Confirm current prerequisites, restrictions and availability with Sheridan College.

Check the official course catalogue

Build an oriented flux integral

For F(x,y,z)=(x,y,z)\mathbf F(x,y,z)=(x,y,z), find the upward flux through the part of z=2−x−yz=2-x-y lying above x≥0x\ge0, y≥0y\ge0, x+y≤2x+y\le2.

Show the reasoning
  1. Describe the projected triangle

    The projection has vertices (0,0), (2,0) and (0,2). One valid order is 0≤x≤20\le x\le2, 0≤y≤2−x0\le y\le2-x. These bounds describe the whole triangle exactly once.

  2. Use an upward oriented area vector

    The symbols gxg_x and gyg_y denote the partial derivatives of gg with respect to xx and yy. For a graph z=g(x,y)z=g(x,y), the upward vector element is (−gx,−gy,1) dx dy=(1,1,1) dx dy(-g_x,-g_y,1)\,dx\,dy=(1,1,1)\,dx\,dy. It already combines the unit normal and surface-area factor; do not multiply by another 3\sqrt3.

  3. Restrict the field to the surface

    On the plane, F=(x,y,2−x−y)\mathbf F=(x,y,2-x-y). Its dot product with (1,1,1) is 2. Therefore the flux is ∫02∫02−x2 dy dx\int_0^2\int_0^{2-x}2\,dy\,dx.

  4. Integrate and check the sign

    The result is ∫02(4−2x) dx=4\int_0^2(4-2x)\,dx=4. Equivalently, multiply the constant integrand 2 by the projected triangle’s area 2. Reversing the orientation would change the flux to −4.

Try a changed problem

Use the same field on z=3−x−yz=3-x-y above x≥0x\ge0, y≥0y\ge0, x+y≤3x+y\le3, now with downward orientation. Find the flux.

Check your reasoning

The downward area vector is (−1,−1,−1) dx dy(-1,-1,-1)\,dx\,dy, giving integrand −3. The projected triangle has area 9/29/2, so the flux is −27/2-27/2. Both the orientation and the region change the result.

How tutoring can help

You can ask for help before knowing which method to use. A tutor can help you compare convergence tests, draw an integration region or choose a surface orientation. We can work through the reasoning together, then apply it to another example.

Exam preparation for MATH15121D

Practise identifying the object and theorem before starting algebra. Check power-series endpoints separately. For vector-calculus questions, state boundary orientation and theorem conditions; a short direct calculation can verify the sign of a theorem-based answer.

Use your section’s outline to choose the chapters to review. We work through permitted practice and comparable problems, without completing graded assignments or exams on your behalf.

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MATH15121D · official course reference