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180 and Cast

Mathematics · Class 11

Second quadrant: sine +. sin(180-A)=+sin A. cos(180-A)=-cos A. Third: tan +. Fourth: cos +. Draw a quick CAST if needed.

ASTC / CAST
reduce to A, then sign from the quadrant
sin(90-A)=cos A
sine + in Q2
180 AND CAST: Second quadrant: sine +. sin(180-A)=+sin A. cos(180-A)=-cos A. Third: tan +. Fourth: cos +. Draw a q
180 AND CAST: Second quadrant: sine +.
WHAT — 180 AND CAST: Second quadrant: sine +. sin(180-A)=+sin A. cos(180-A)=-cos A. Third: tan +. Fourth: cos +. Draw a q
WHY — Why it matters: This rule is a separate learning unit inside allied angles. It can be defined, applied, and checked

Right triangle — 180 and Cast — original sketch for this lesson (not copied from a textbook).