1200 тенге + 4% или 1200 * 1,04= 1248 тенге
АВ²=АС²+ВС²
АВ²=400+441=841
АВ=29
cosВ= ≈0,72
Ответ:0,72
1/(1+√2) = (√2–1)/((√2–1)(√2+1)) = (√2–1)/(2–1) = √2–1,
1/(√2+√3) = (√3–√2)/((√3–√2)(√3+√2)) = (√3;–√2)/(3–2) = √3–√2,
. .
1/(√2004+√2005) = (√2005–√2004)/((√2005–√2004)(√2005+√2004)) = (√2005–√2004)/(2005–2004) = √2005–√2004.
<span>Сумма равна √2–1+√3–√2+…+√2005–√2004 = √2005–1.</span>
№3 2*1,2-2*1,2+3*3=9
№2. а) 3x (x-1)-2 (1-x)=3x^2-3x-2+2x=3x^2-x-2
б) 4ab-8ac+b^2-2bc=4a (b-2c)+b(b-2c)=(4a+b) (b-2c)
^2- это степень, остальное не умею :)
A=4, b=5, c=1<br />D=25-4*4*1=25-16=9<br />x1=-5+3/8=-2/8=-1/4=0,25
x2=-5-3/8=8/8=1
Ответ: 1