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Ask iit jee aieee pet cbse icse state board community Community Discussion Question: No.of solutions possible
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pradeepdin.11 (55)

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2^cosx = |sin x|    within the interval (0,2pi)


Ans : 2;


How to solve....................:(

    
ABHI_23 (1023)

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well you can easily try it by observation


as x =  0r


BEST OF LUCk

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ABHI_23 (1023)

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can anyone tell the systematic way of solving the problem!!!!?????

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harsha123456789 (0)

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min value of 2^cosx=1 max value of sinx=1 therefore solution is one as mod is given 2 solutions

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ABHI_23 (1023)

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NO, man you are wrong !!!!!!!!


min value of  is not 0 as cosx can be -ve also


cosx (-1,1) so min value = 1/2


best of luck


plz  somebody give the correct ans with systematic soln

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spideyunlimited (4185)

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2^cosx = |sin x| within the interval (0,2pi)

Just draw the graphs of both expressions
2^cosx (and cos varies from -1 to 1, so draw accordingly)
And |sinx| , draw the sin graph and invert everything to positive y axis. Then you'll easily see the number of intersections between the 2 graphs which is equal to the number of solutions.

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spideyunlimited (4185)

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Acc. to graph, there are 4 solutions! not 2.


 



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jinique (23)

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right abt the minimum value of 2^cosx........ its not zero
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jinique (23)

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hey bro @ SPIDY ........ CAN U PLEASE depict the graph in kind o detail ?
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spideyunlimited (4185)

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Least value of 2^ cosx = 1/2 and max value is 2.

Click on the graph to view in detail.

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jinique (23)

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hey bro @ SPIDY ........ CAN U PLEASE depict the graph in kind o detail ?
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spideyunlimited (4185)

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since cos varies from -1 to 1, so 2^cosx varies from 1/2 to 2.
And sin x graph , i think you know. So mod of that graph will have everything reflected above x axis.

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venkat_tatolu (228)

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graph is absolutely correct.So the no. of solutions in given interval is 4."This is the right answer .

***T.Venkat***
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