Sinx and cosx in the second quadrant

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Start date Jan 11, 2015

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tmt1

Thread starter
Jan 11, 2015

In a question we have sinx > 0 and cosx < 0.

The book says that from this we can determine that angle x is in the second quadrant. I am not understanding this leap.

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MarkFL

Gold Member

MHB

Jan 11, 2015

Think of the unit circle...in which quadrant do points on the circle have negative $x$-coordinates and positive $y$-coordinates?

Sinx and cosx in the second quadrant

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Sinx and cosx in the second quadrant

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