The doctrine of triangles a history of modern trigonometry حسب Van Brummelen, Glen

Available for University of the Philippines Diliman via IEEE Xplore. Click here to access
Also available remotely for University of the Philippines Diliman via IEEE Xplore. Click here to access thru EZproxy

Schaum's outline of precalculus حسب Safier, Fred

Available for University of the Philippines Diliman via McGraw-Hill Access Engineering. Click here to access
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Algebra and trigonometry حسب Sullivan, Michael

Precalculus functions and graphs حسب Swokowski, Earl William 1926-, Cole, Jeffery A. (Jeffery Alan) 1955-

Precalculus functions & graphs حسب Swokowski, Earl W.

Three-way journal writing effects on students' problem-solving and self-regulation skills in trigonometry حسب Lugtu, Ivy C.

Schaum's outline of trigonometry حسب Moyer, Robert, Ayres, Frank 1901-1994

Available for University of the Philippines Diliman via McGraw-Hill Access Engineering. Click here to access
Also available remotely for University of the Philippines Diliman via McGraw-Hill Access Engineering. Click here to access thru EZproxy

The fractional trigonometry with applications to fractional differential equations and science حسب Lorenzo, Carl F., Hartley, Tom T.

A basic approach to precalculus trigonometry preparing to succeed in calculus حسب Kim, Young H., Kim, Youngsoo, Tameru, Ana, Yan, Wen

Plane & spherical trigonometry a tetrahedron approach حسب Mamhot, Millard R., Endam, Joemar C., Mamhot, Alice A., Banagua, Emelyn C., Bantug, Jenette S.