1+tg^2 a=1/cos^2 a
tg^2 a=1/cos^2 a -1
tg^2 a=10-1
tg a=+-3 так как а принадлежит промежутку то
tg a =-3
2,25^1/7*4^1/7*4^1/7*36^6/7=(2?25*4*4)^1/7*36^6/7=36^1/7*36^6/7=36^7/7=36
8(x+2)-6=8+(5+8x)2
8x+16-6=8+10+16x
8x-16x=8+10+6
-8x=24
-x=24:8
-x=3
x=-3
D=25-4*3а = 25-12а > 0
x₁=(5+√(25-12а))/6
x₂=(5-√(25-12а))/6
x₁² - x₂² = (5+√(25-12а))²/36 - (5-√(25-12а))²/36 = 5/9
(5+√(25-12а))² - (5-√(25-12а))² = 20
(5+√(25-12а) - 5+√(25-12а))*(5+√(25-12а) + 5-√(25-12а)) = 20
2√(25-12а)*10 = 20
√(25-12а) = 1
25-12а = 1
12а = 24
a=2
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