Whakaoti i te 400000=200000*1.04^x

$$400000=200000 \times { 1.04 }^{ x }$$

Whakaoti mō x

$$x=\log_{1.04}\left(2\right)\approx 17.672987685$$

Ngā Upane e Whakamahi ana i te Tautuhinga o te Taupū Kōaro

Whakawehea ngā taha e rua ki te 200000.

$$\frac{400000}{200000}=1.04^{x}$$

Whakawehea te 400000 ki te 200000, kia riro ko 2.

$$2=1.04^{x}$$

Whakawhitihia ngā taha kia puta ki te taha mauī ngā kīanga tau taurangi katoa.

$$1.04^{x}=2$$

Tuhia te tau taupū kōaro o ngā taha e rua o te whārite.

$$\log(1.04^{x})=\log(2)$$

Ko te taupū kōaro o tētahi tau ka hīkina ki tētahi pū ko te pū whakarea ki te taupū kōaro o taua tau.

$$x\log(1.04)=\log(2)$$

Whakawehea ngā taha e rua ki te \log(1.04).

$$x=\frac{\log(2)}{\log(1.04)}$$

Mā te tikanga tātai huri pūtake \frac{\log(a)}{\log(b)}=\log_{b}\left(a\right).

$$x=\log_{1.04}\left(2\right)$$

Whakaoti mō x (complex solution)

$$x=\frac{i\times 2\pi n_{1}}{\ln(1.04)}+\log_{1.04}\left(2\right)$$

$$n_{1}\in \mathrm{Z}$$