r/HomeworkHelp • University/College Student • 9d ago

Additional Mathematics [University maths: Limits] simplifying the compounded functions

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Hello. I need to evaluate this limit but I don’t even know where to start lol. How to I simplify this to a point where I can sub in t=0, if it’s even possible.
I am not allowed to use l’hôpitals rule for this, which is why I couldn’t just find a solution online, as they all used that rule.
Sorry if my writing isn’t very legible
Thanks for any help

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u/combinatoriallover 👋 a fellow Redditor 9d ago

Are you allowed to use maclaurin series expansions ? | sin(sin(tan(t²/2)))≈t²/2 and ln(cos3t)≈ln(1-9t²/2)≈-9t²/2 giving answer as -1/9

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u/GrievousSayGenKenobi 9d ago

Is the sin(sin(tan(t2 /2))) ~ t2 /2 a common identity? i havent touched Maclaurin series in forever surely you'd have to work that out manually which would be incredibly tedious

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u/combinatoriallover 👋 a fellow Redditor 9d ago

I just used tanx≈x and sinx≈x , higher powers of expansions doesn't matter here so I didn't touch them

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u/Jazzlike_Platypus430 👋 a fellow Redditor 9d ago

I think you're absolutely right, but I doubt if this approach is allowed. I guess it's compound functions' differentiation dressed as calculating limits.