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# trigonometrical identities no long ting people watch

1. okay so why does it say its minus at the end of the solution of the question cos like 4/3 should be on the 3Rd quadrant and 3Rd quadrant means tan should be positive and 4/5 should be right but only the tan as you can see in the picture i don't understand why its minus some please explain thanx people
btw the thing confusing me is at the end of the solution and also the equals sign doesnt show properly so just to let u know the bold dashes that look minuses are equal signs and minus signs are minuses but not bold
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2. Not sure I follow you. To figure out what sign should be associated with a trig function, use CAST. In your thumbnail, the angle is in the second quadrant in which only sine is positive. Everthing else, for example tan, is negative. To understand CAST, go back to the definition. Does that answer your question?

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Updated: April 10, 2011
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