Réitigh 78=1/2*9.8t^2

$$78 = \frac { 1 } { 2 } \times 9.8 t ^ { 2 }$$

Réitigh do t.

$$t = \frac{2 \sqrt{195}}{7} \approx 3.98978287$$

$$t = -\frac{2 \sqrt{195}}{7} \approx -3.98978287$$

Céimeanna tríd an bhFréamh Chearnach a Fháil

Méadaigh \frac{1}{2} agus 9.8 chun \frac{49}{10} a fháil.

$$78=\frac{49}{10}t^{2}$$

Athraigh na taobhanna ionas go mbeidh na téarmaí inathraitheacha ar fad ar an taobh clé.

$$\frac{49}{10}t^{2}=78$$

Iolraigh an dá thaobh faoi \frac{10}{49}, an deilín de \frac{49}{10}.

$$t^{2}=78\times \frac{10}{49}$$

Méadaigh 78 agus \frac{10}{49} chun \frac{780}{49} a fháil.

$$t^{2}=\frac{780}{49}$$

Tóg fréamh chearnach an dá thaobh den chothromóid.

$$t=\frac{2\sqrt{195}}{7} t=-\frac{2\sqrt{195}}{7}$$

Céimeanna ag Baint Úsáid as an bhFoirmle Chearnach

Méadaigh \frac{1}{2} agus 9.8 chun \frac{49}{10} a fháil.

$$78=\frac{49}{10}t^{2}$$

Athraigh na taobhanna ionas go mbeidh na téarmaí inathraitheacha ar fad ar an taobh clé.

$$\frac{49}{10}t^{2}=78$$

Bain 78 ón dá thaobh.

$$\frac{49}{10}t^{2}-78=0$$

Tá an chothromóid seo i bhfoirm chaighdeánach: ax^{2}+bx+c=0. Cuir \frac{49}{10} in ionad a, 0 in ionad b, agus -78 in ionad c san fhoirmle chearnach, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.

$$t=\frac{0±\sqrt{0^{2}-4\times \frac{49}{10}\left(-78\right)}}{2\times \frac{49}{10}}$$

Cearnóg 0.

$$t=\frac{0±\sqrt{-4\times \frac{49}{10}\left(-78\right)}}{2\times \frac{49}{10}}$$

Méadaigh -4 faoi \frac{49}{10}.

$$t=\frac{0±\sqrt{-\frac{98}{5}\left(-78\right)}}{2\times \frac{49}{10}}$$

Méadaigh -\frac{98}{5} faoi -78.

$$t=\frac{0±\sqrt{\frac{7644}{5}}}{2\times \frac{49}{10}}$$

Tóg fréamh chearnach \frac{7644}{5}.

$$t=\frac{0±\frac{14\sqrt{195}}{5}}{2\times \frac{49}{10}}$$

Méadaigh 2 faoi \frac{49}{10}.

$$t=\frac{0±\frac{14\sqrt{195}}{5}}{\frac{49}{5}}$$

Réitigh an chothromóid t=\frac{0±\frac{14\sqrt{195}}{5}}{\frac{49}{5}} nuair is ionann ± agus plus.

$$t=\frac{2\sqrt{195}}{7}$$

Réitigh an chothromóid t=\frac{0±\frac{14\sqrt{195}}{5}}{\frac{49}{5}} nuair is ionann ± agus míneas.

$$t=-\frac{2\sqrt{195}}{7}$$

Tá an chothromóid réitithe anois.

$$t=\frac{2\sqrt{195}}{7} t=-\frac{2\sqrt{195}}{7}$$