X^2 = 2x+ 3
x^2 - 2x - 3 = 0
D = 4 + 12 = 16
x1 = ( 2 + 4)/2 = 6/2 = 3
x2 = ( 2 - 4)/2 = - 2/2 = - 1
x1 = 3
y1 = 3^2 = 9
x2 = - 1
y2 = (-1)^2 = 1
Ответ
(3; 9) ; ( - 1; 1)
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(1- sin^4a-cos^4a)/cos^4a =
(4-3-cos4a/4) /cos^4a =
(1-cos4a)/4cos^4a =
(8cos^2a- 8 cos^4a)/4cos^4a = (2/cos^2a) -2=(2-2cos^2a)/cos^2a