Understanding Limits: Evaluating Tricky Expressions

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This discussion focuses on evaluating limits in calculus, specifically the limits as x approaches infinity and pi. For the first limit, lim (x--> inf.) (3x^3 + cos x)/(sin x - x^3), the correct approach is to factor out x^3 from both the numerator and denominator, leading to a limit of -3. For the second limit, lim (x--> Pie(+)) (tan^-1 (1/(x-Pie)))/(Pie-x), the numerator approaches pi/2 while the denominator approaches 0, indicating that the limit diverges to infinity.

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johnq2k7
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2.) Evaluate the following limits, justifying your answers. If a limit does not exist explain why.

a.) lim (x--> inf.) (3x^3 +cos x)/(sin x- x^3)


b.) lim (x-->Pie(+)) (tan^-1 (1/(x-Pie)))/(Pie-x


I have no idea, what do here please help me with these problems!
 
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For a, factor x^3 from both terms in the numerator and both terms in the denominator.
For b, if I'm interpreting what you wrote correctly, the numerator is approaching pi/2 (note spelling -- the name of this Greek letter is pi, not pie), and the denominator is approaching 0, so the quotient is getting large without bound.
 

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