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If s in A=3/4 , calculate cos A an...

If `s in A=3/4` , calculate cos A and tan A.

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`sinA=(3)/(4)` Construct `DeltaABC` , right - angled at B such that
`BC=3kandAC=4k`
In `DeltaABC`,
From Pythagoras theorem
`AB^(2)=AC^(2)-BC^(2)=(4k)^(2)-(3k)^(2)=16k^(2)=9k^(2)=7k^(2)`
`rArrAB=sqrt(7)k`
Now , `cosA=(AB)/(AC)=(sqrt(2)k)/(4k)=(sqrt7)/(4)`
`tan A=(BC)/(AB)=(3k)/(sqrt(7)k)=(3)/(sqrt(7))`
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NAGEEN PRAKASHAN ENGLISH-INTRODUCTION TO TRIGONOMETRY-Problems From NCERT/exemplar
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  11. Prove (tantheta+2)(2tantheta+1)=5tantheta+2sec^2theta.

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  16. about to only mathematics

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  17. If 2sin^(2)theta-cos^(2)theta=2, then find the value of theta.

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  18. if tantheta+sectheta=l then prove that sectheta=(l^2+1)/(2l)

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  19. If asintheta+bcostheta=c then prove that acostheta-bsintheta=sqrt(a^2+...

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