The Cosine Rule — الرياضيات البحتة الصف الثاني الثانوي لغات

درس «The Cosine Rule» فى مادة الرياضيات البحتة لـالصف الثاني الثانوي لغات من وحدة «Unit 4: Trigonometry». This lesson establishes the Cosine Rule for finding unknown sides and angles of any triangle: a^2 = b^2 + c^2 - 2bc cos(A), cos(A) = (b^2 + c^2 - a^2) / (2bc), solving SAS and SSS triangle configurations, and solving geometric applications involving parallelograms, trapezoids, and cyclic quadrilaterals. هتتعلم فى الدرس ده: Side formulas: a^2 = b^2 + c^2 - 2bc cos(A), b^2 = a^2 + c^2 - 2ac cos(B), c^2 = a^2 + b^2 - 2ab cos(C).، Angle formulas: cos(A) = (b^2 + c^2 - a^2) / (2bc), cos(B) = (a^2 + c^2 - b^2) / (2ac), cos(C) = (a^2 + b^2 - c^2) / (2ab).، The Cosine Rule generalizes the...

الدرس ده من وحدة «Unit 4: Trigonometry» فى مادة الرياضيات البحتة لـالصف الثاني الثانوي لغات على منصة دروسات.

الدرس متاح بالاشتراك: ترم كامل أو المادة لوحدها.

ملخص الدرس

This lesson establishes the Cosine Rule for finding unknown sides and angles of any triangle: a^2 = b^2 + c^2 - 2bc cos(A), cos(A) = (b^2 + c^2 - a^2) / (2bc), solving SAS and SSS triangle configurations, and solving geometric applications involving parallelograms, trapezoids, and cyclic quadrilaterals.

هتتعلم إيه فى الدرس ده

• Side formulas: a^2 = b^2 + c^2 - 2bc cos(A), b^2 = a^2 + c^2 - 2ac cos(B), c^2 = a^2 + b^2 - 2ab cos(C).
• Angle formulas: cos(A) = (b^2 + c^2 - a^2) / (2bc), cos(B) = (a^2 + c^2 - b^2) / (2ac), cos(C) = (a^2 + b^2 - c^2) / (2ab).
• The Cosine Rule generalizes the Pythagorean Theorem (when angle = 90°, cos(90°) = 0).
• If cos(A) > 0, angle A is acute; if cos(A) < 0, angle A is obtuse; if cos(A) = 0, angle A is right.
• Essential for solving triangles when given two sides and the included angle (SAS) or all three sides (SSS).