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Evaluate :i) tan 36°/cot 54°ii) cos 12° - sin 78°iii) cosec 31° - sec 58°​

Answer»

HELLO FRIEND!!!!!!

QUESTION 1:

\frac{ \tan(36) }{ \cot(54) }

we know the identity that :

\tan(90 - theeta)  =  \cot(theeta)

thus,

\tan(36)  =  \tan(90 - 36)

\tan(36)  =  \cot(54)

thus equation becomes:

\frac{ \cot(54) }{ \cot(54) }

1

thus answer of question 1 is 1

question 2

\cos(12)  -  \sin(78)

again using same identity,

where theeta is 12 degree....

\cos(12)   =   \sin(90 - 12)

\cos(12)  =  \sin(78)

so equation becomes...

\sin(78)  -  \sin(78)

which is 0.....

thus answer of question 2 becomes 0

question 3

\csc(31)  -  \<klux>SEC</klux>(58)

using same identity ...

\csc(31)  =  \csc(90 - 59)

so here there is an ERROR in question...the question should be sec 59 degree .....

\sec(58)

-  \sec(58)

which is 0

thus answer of corrected question 3 would be 0 ..

THANK YOU



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