Finding the Integral of csc^2x: What to Do When Tanx is Undefined at pi/6?

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SUMMARY

The integral of csc²x from π/6 to π/2 can be computed using the substitution method. The correct transformation involves recognizing that cot²x can be expressed as csc²x - 1. The integral simplifies to tan³x/3 evaluated at the limits π/6 and π/2. The confusion regarding the undefined nature of tan at π/6 is clarified by noting that tan(π/6) is indeed defined and equals 1/√3.

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  • Familiarity with trigonometric identities, particularly csc and cot functions.
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Homework Statement


find the integral of (cscx)2 between pie/6 to pie/2




The Attempt at a Solution



cot2x = 1 / sin2x * cos2x / cos2x
which becomes..
tan2x * sec2x
then i substituted u for tan x, and turned the integral into..
u2du = u3 / 3
which is..
tan3x / 3 between pie/6 and pie/2.

However, tan is undefined at pie/6! what do i do?
 
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Eshi said:
cot2x = 1 / sin2x * cos2x / cos2x
which becomes..
tan2x * sec2x

No, that last line should be cot2x * sec2x, and the cot in the first line should be csc.

However, tan is undefined at pie/6! what do i do?

That's not true; it is defined at [itex]\pi[/itex]/6. What is sin[itex]\pi[/itex]/6 and cos[itex]\pi[/itex]/6? Put sine over cosine.
 

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