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Sir, We all know that in the first quadrant all trignometric functions are positive, In second quadrant sine and cosec are positive. My question is that why the value of cosx is -ve in second quadrant where as the trignometric function cosx is ratio of lenghts (Base/Hypotenuse) and the lenghts cannot be in -ve. Please tell me answer as soon as possible..... From:- Zippinderpal Singh, Class:-XII Email-ID:- zippinderpalsingh@yahoo.in

Sir,
We all know that in the first quadrant all trignometric functions are positive, In second quadrant sine and cosec are positive. My question is that why the value of cosx is -ve in second quadrant where as the trignometric function cosx is ratio of lenghts (Base/Hypotenuse) and the lenghts cannot be in -ve. Please tell me answer as soon as possible.....
From:- Zippinderpal Singh, Class:-XII
Email-ID:- zippinderpalsingh@yahoo.in

Grade:12

1 Answers

Vanya Saxena
18 Points
13 years ago

HI,

 

Since cosx is the ratio of lengths i.e. base /hypotenuse and we know that in the second quadrant  x-axis has all the -ve values of x whereas the hypotenuse is positve thus on taking the ratio we get a -ve value. Because the base has a negative value

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