Co-aontaran triantanachd a' cleachdadh foirmlean nan ceàrnan dùbailte
Faodaidh tu ath-sgrùdadh a dhèanamh air na tha fios agad mu fhoirmlean cheàrnan dùbailte mar phàirt de Abairtean agus Fuincseanan.
Eisimpleir
Fuasgail an co-aontar \(5\sin 2x^\circ + 7\cos x^\circ = 0\), airson \(0^\circ \le x^\circ \le 360^\circ\).
Fuasgladh
\(5\sin 2x^\circ + 7\cos x^\circ = 0\)
An àite \(\sin 2x^\circ\) cuir \(2\sin x^\circ \cos x^\circ\)
\(5(2\sin x^\circ \cos x^\circ ) + 7\cos x^\circ = 0\)
Iomadaich a-mach na camagan:
\(10\sin x^\circ \cos x^\circ + 7\cos x^\circ = 0\)
Thoir a-mach \(\cos x^\circ\) mar fhactar cumanta.
\(\cos x^\circ (10\sin x^\circ + 7) = 0\)
Tha dà fhuasgladh comasach ann:
\(\cos x^\circ = 0\)
\(10\sin x^\circ + 7 = 0\)
Fuasgail na co-aontaran fear mu seach:
\(\cos x^\circ = 0\)
\(x^\circ = 90^\circ\) no \(270^\circ\)
Agus:
\(10\sin x^\circ + 7 = 0\)
\(10\sin x^\circ = - 7\)
\(\sin x^\circ = - \frac{7}{{10}}\)
\(x^\circ = 224.4^\circ\) no \(315.6^\circ\)
Agus tha sin a' toirt nam fuasglaidhean \(90^\circ ,\,224.4^\circ ,\,270^\circ ,\,315.6^\circ\)
