Question

решите уравнение 4t2-2t-1=0
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Answer 1

$4t^2-2t-1=0\\\\x_{1,\:2}=\frac{-b\pm \sqrt{b^2-4ac}}{2a}\\\\a=4,\:b=-2,\:c=-1:\quad t_{1,\:2}=\frac{-\left(-2\right)\pm \sqrt{\left(-2\right)^2-4\cdot \:4\left(-1\right)}}{2\cdot \:4}\\\\t_1=\frac{2+\sqrt{20}}{8}=\frac{2+2\sqrt{5}}{8}=\frac{2\left(1+\sqrt{5}\right)}{8}=\frac{1+\sqrt{5}}{4}\\\\t_2=\frac{1-\sqrt{5}}{4}$