1)=-cosπ/4=-√2/2
2)0,sin30/-cos30=-0,5tg30=-1/2√3=-√3/6
3)sin2α-cos2α+2=2sinacosa-cos²a+sin²a+2sin²a+2cos²a=3sin²a+cos²a+2sinacosa
sin²a=1:(1+ctg²a)=1:(1+4)=1/5⇒cos²a=1-1/5=4/5
sina=1/√5 U cosa=2/√5
sin2α-cos2α+2=3*1/5+4/5+2*1/√5*2/√5=3/5+4/5+4/5=11/5
sin²α-2cos²α=1/5-2*4/5=1/5-8/5=-7/5
(sin2α-cos2α+2)/sin²α-2cos²α=11/5:(-7/5)=-11/5*5/7=-11/7

0 0

4 года назад

|x|>2 Напишите решение пожалуйста

yernurrr

$|x|\ \textgreater \ 2\; \; \Rightarrow \; \; x\in (-\infty ,-2)\cup (2,+\infty ) \\\\\\a)\; \; x\ \textless \ 0\; \; \to \; \; |x|=-x\; \; \to \; \; -x\ \textgreater \ 2\; ,\; \; x\ \textless \ -2\\\\b)\; \; x=0\; \; \to |x|=|0|=0\; ,\; \; 0\ \textgreater \ 2\; \; neverno\\\\c)\; \; x\ \textgreater \ 0\; \; \to \; \; |x|=x\; \; \to \; \; x\ \textgreater \ 2\\\\Vuvod:\; \; |x|\ \textgreater \ 2\; \; \Rightarrow \; \; \left [ {{x\ \textless \ -2} \atop {x\ \textgreater \ 2}} \right. \; \; \Rightarrow \; \; x\in (-\infty ,-2)\cup (2,+\infty )$

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0 0

2 месяца назад