1.

Evaluate `lim_(xto0) (1-cos2x)/x^(2)`A. 2B. 1C. 4D. 3

Answer» Correct Answer - A
Given, `underset(xto0)"lim"(1-cos2x)/x^(2) = underset(xto0)"lim"(1-1+2sin^(2)x)/(x^(2))` `[therefore cos2x=1-2sin^(2)x]`
`=underset(xto0)"lim"(2sin^(2)x)/(x^(2))=2 underset(xto0)"lim"(sin^(2)x)/(x^(2))`
`=2underset(xto0)"lim"((sinx)/x)^(2)` `[therefore underset(xto0)"lim"(sinx)/x=1]`
`=2 xx 1=2`


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