Math Problem Statement

what is the integral of -8t5/(t2+2)**1/2

Solution

We need to evaluate the integral:

I=8t5(t2+2)1/2dtI = \int \frac{-8t^5}{(t^2+2)^{1/2}} \, dt

Step 1: Substitution

Let: u=t2+2u = t^2 + 2 Then, differentiate both sides: du=2tdtdu2=tdtdu = 2t \, dt \quad \Rightarrow \quad \frac{du}{2} = t \, dt

Step 2: Express in Terms of uu

Rewriting t5t^5 as: t5=t3t2=t3(u2)t^5 = t^3 \cdot t^2 = t^3 (u - 2)

Since t3=tt2t^3 = t \cdot t^2, we use t2=u2t^2 = u - 2 and get: t3=t(u2)t^3 = t(u - 2)

Using tdt=du2t \, dt = \frac{du}{2}, the integral transforms into:

I=8t3(u2)u1/2dtI = \int \frac{-8 t^3 (u - 2)}{u^{1/2}} \cdot dt

Substituting t3=t(u2)t^3 = t(u - 2):

I=8(u2)tu1/2dtI = \int \frac{-8 (u - 2)t}{u^{1/2}} \cdot dt

Since tdt=du2t \, dt = \frac{du}{2}, we substitute:

I=8(u2)u1/2du2I = \int \frac{-8 (u - 2)}{u^{1/2}} \cdot \frac{du}{2}

I=4(u2)u1/2duI = \int \frac{-4 (u - 2)}{u^{1/2}} \, du

Step 3: Split the Integral

I=4uu1/2du+81u1/2duI = -4 \int \frac{u}{u^{1/2}} \, du + 8 \int \frac{1}{u^{1/2}} \, du

Simplify:

I=4u1/2du+8u1/2duI = -4 \int u^{1/2} \, du + 8 \int u^{-1/2} \, du

Step 4: Evaluate the Integrals

Using the power rule undu=un+1n+1\int u^n \, du = \frac{u^{n+1}}{n+1}:

u1/2du=u3/23/2=23u3/2\int u^{1/2} \, du = \frac{u^{3/2}}{3/2} = \frac{2}{3} u^{3/2}

u1/2du=u1/21/2=2u1/2\int u^{-1/2} \, du = \frac{u^{1/2}}{1/2} = 2u^{1/2}

So,

I=423u3/2+82u1/2I = -4 \cdot \frac{2}{3} u^{3/2} + 8 \cdot 2 u^{1/2}

I=83u3/2+16u1/2+CI = -\frac{8}{3} u^{3/2} + 16 u^{1/2} + C

Step 5: Substitute Back u=t2+2u = t^2 + 2

I=83(t2+2)3/2+16(t2+2)1/2+CI = -\frac{8}{3} (t^2+2)^{3/2} + 16 (t^2+2)^{1/2} + C

Final Answer:

I=83(t2+2)3/2+16(t2+2)1/2+C\boxed{I = -\frac{8}{3} (t^2+2)^{3/2} + 16 (t^2+2)^{1/2} + C}

Would you like more details or another approach?

Here are 5 related questions:

  1. How do you choose an appropriate substitution for integrals?
  2. What is the power rule for integration, and how is it applied?
  3. How do you integrate expressions with square roots?
  4. How can integration by parts be applied to different functions?
  5. How do definite integrals differ from indefinite integrals?

Tip: Always check if substitution simplifies the integral before trying more complex techniques!

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Math Problem Analysis

Mathematical Concepts

Integration
Substitution
Power Rule for Integration

Formulas

\int u^n du = \frac{u^{n+1}}{n+1}
Substitution: \nu = t^2 + 2
Power Rule: \int u^{n} du = \frac{u^{n+1}}{n+1}

Theorems

Substitution method for integrals
Power rule for integration

Suitable Grade Level

Grades 11-12