Cos100/cos50+sin50 -(cos^2 25-sin^2 25)​

объяснение:

[tex]\frac{cos100}{cos50} +sin50-(cos^{2}25 - sin^{2}25 ) =\frac{cos100}{cos50}+sin50-cos50 =\frac{cos^250-sin^250-cos^250}{cos50}+sin50=sin50-tg50sin50=sin50(1-tg50)[/tex]

ответ:

[tex]sin50(1-tg50)[/tex]

а(5) = а(3) + 2d

а(10) = а(3) + 7d

30+15=45

45/2=22,5%