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

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Schaum's outline of precalculus af Safier, Fred

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

Precalculus functions and graphs af Swokowski, Earl William 1926-, Cole, Jeffery A. 1955-

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

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

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

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

Worktext in college trigonometry af Domingo, Alleli C., Dimasuay, Lynie B., Lawas, Vernel M., Lubag, Sharon P., Almonte, Velimor D.

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