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Question
Evaluate the following limits:
`lim_(x -> 0) (tan 2x)/x`
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Solution
We know `lim_(x -> 0) (sinx)/x` = 1
`lim_(x -> 0) (tan 2x)/x = lim_(x -> 0) (sin 2x)/(cos 2x) xx 1/x`
= `lim_(x -> 0) (sin 2x)/(1/2 xx (2x)) xx 1/(cos 2x)`
= `2(lim_(2x -> 0) (sin 2x)/(2x)) (lim_(x -> 0) 1/(cos 2x))`
= `2 xx 1 xx 1/(cos 0)`
`lim_(x -> 0) (tan 2x)/x = 2 xx 1 xx 1`
= 2
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