Применим правило Лопиталя:
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= 1.
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limit( (exp(x) - 1)/(sin(x)), x = 0);
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ac:= plot((exp(x) - 1)/(sin(x)), x = -1..-0.001, color = red):
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bc:= plot((exp(x) - 1)/(sin(x)), x = 0.001..1, color = red):
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cc:= plot([x,1,x = -0.5..0.5], color = magenta):
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display((ac,bc,cc));