Co-aontaran triantanachd anns a bheil ceàrnan fà-fhillte (leudachadh)

Eisimpleir

Fuasgail an co-aontar 5\cos (6x - 20)^\circ  + 3 = 7.25, airson 0 \le x \le 180.

Fuasgladh

5\cos (6x - 20)^\circ  + 3 = 7.25

5\cos (6x - 20) = 4.25

\cos (6x - 20) = 0.85

Bhon a tha cos dearbhte, tha sinn sa 1d agus sa 4mh cairteal.

A' chiad chairteal

6x - 20 = 31.8^\circ

6x = 51.8^\circ

x = 8.6^\circ

An ceathramh cairteal

6x - 20 = 360^\circ  - 31.8^\circ

6x - 20 = 328.2^\circ

6x = 348.2^\circ

x = 58.0^\circ

Bhon a tha 0 \le x \le 180, feumaidh sinn na toraidhean eile a lorg le bhith a' cur na peiriad ris na fuasglaidhean seo.

Peiriad = 360^\circ  \div 6 = 60^\circ

3mh fuasgladh: 8.6 + 60 = 68.6^\circ

4mh fuasgladh: 58.0 + 60 = 118^\circ

5mh fuasgladh: 68.6 + 60 = 128.6^\circ

6mh fuasgladh: 118 + 60 = 178^\circ

7mh fuasgladh: 128.6 + 60 = 188.6^\circ. Chan e fuasgladh a tha seo bhon a tha 0 \le x \le 180.

Mar sin x^\circ  = 8.6^\circ ,\,58^\circ ,\,68.6^\circ ,\,118^\circ,\,128.6^\circ,\,178^\circ,\,188.6^\circ