1)5<span><span>(<span>a+b</span>)^</span>2</span>−10ab=5<span>(<span><span>a^2</span>+2ab+<span>b^2</span></span>)</span>−10ab= 5<span>a^2</span>+10ab+5<span>b^2</span>−10ab=5a^2+5b^2
2)<span><span>(<span>2b+<span>b^2</span></span>)^</span>2</span>+<span>b^2</span><span>(<span>5−b</span>)</span><span>(<span>5+b</span>)</span>−4b<span>(<span><span>b^2</span>−3</span>)= </span>4<span>b^2</span>+4<span>b^3</span>+<span>b^4</span>+<span>(<span><span>b^2</span>⋅5- <span>b^3</span></span>)</span><span>(<span>5+b</span>)</span>−4<span>b3</span>+12b= 4<span>b^2</span>+<span>b^4</span>+<span>(<span>5<span>b^2</span>−<span>b^3</span></span>)</span><span>(<span>5+b</span>)</span>+12b= =b^2+b^4+25b^2+5b^3−5b^3−b4+12b=29<span>b^2</span>+12<span>b</span>
Cos(t)/sin(t)*1/(sin(t)/cos(t)+cos(t)/sin(t))=cos(2t)
(cos(t))^2=cos(2t)
(sin(t))^2=0
sin(t)=0
t = n*pi
Решение:
3*10^-2+4*10^-3+9*10^-4=3/100+4/1000+9/10000=(100*3+10*4+9)/10000=(300+40+9)/10000=349/10000=0,0349
Ответ: 0,0349
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Ответ:
1/9+5/18 приводим к общему знаменателю
2/18+5/18=7/18