Q. Find the value of ∫1511−2x6dx. Express your answer as a constant times ln3.Answer: □ln3
Identify Integral: Let's first identify the integral we need to solve:I=∫1511−2x6dxWe can start by performing a u-substitution where u=11−2x, which means du=−2dx.
Perform u-Substitution: Now we solve for dx in terms of du:dx=−2duWe also need to change the limits of integration. When x=1, u=11−2(1)=9. When x=5, u=11−2(5)=1.
Solve for dx: Substitute u and dx into the integral:I=∫u=9u=1u6(−2du)This simplifies to:I=−3∫u=9u=1udu
Change Limits of Integration: We can now integrate with respect to u:I=−3[ln∣u∣] from u=9 to u=1
Substitute u and dx: Now we apply the limits of integration: I=−3[ln∣1∣−ln∣9∣] Since ln∣1∣=0, this simplifies to: I=−3[−ln∣9∣]
Integrate with Respect to u: We know that ln∣9∣=ln(32)=2ln(3), so we can substitute this in:I=−3[−2ln(3)]I=6ln(3)
Apply Limits of Integration: Finally, we express the answer as a constant times ln3:I=6ln(3)
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