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Find the value of sin30^(@) geometricall...

Find the value of `sin30^(@)` geometrically.

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To find the value of \( \sin 30^\circ \) geometrically, we can follow these steps: ### Step 1: Draw an Equilateral Triangle Draw an equilateral triangle \( ABC \) where each side is of length \( A \). ### Step 2: Draw the Perpendicular Bisector Draw the perpendicular bisector \( AD \) from vertex \( A \) to the midpoint \( D \) of side \( BC \). This line \( AD \) is perpendicular to \( BC \). ### Step 3: Identify Angles Since triangle \( ABC \) is equilateral, each angle is \( 60^\circ \). The line \( AD \) bisects angle \( A \), so angle \( BAD \) is \( 30^\circ \) (i.e., \( 60^\circ / 2 \)). ### Step 4: Analyze Triangle \( ADC \) In triangle \( ADC \): - The hypotenuse \( AC \) is equal to \( A \). - The side opposite angle \( 30^\circ \) (which is \( AD \)) is half of \( BC \), so it is \( \frac{A}{2} \). ### Step 5: Apply the Sine Definition Using the definition of sine: \[ \sin(30^\circ) = \frac{\text{opposite}}{\text{hypotenuse}} = \frac{AD}{AC} \] Substituting the lengths we identified: \[ \sin(30^\circ) = \frac{\frac{A}{2}}{A} \] ### Step 6: Simplify the Expression Simplifying the expression gives: \[ \sin(30^\circ) = \frac{1}{2} \] ### Conclusion Thus, the value of \( \sin 30^\circ \) is \( \frac{1}{2} \). ---
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NAGEEN PRAKASHAN ENGLISH-INTRODUCTION TO TRIGONOMETRY-Revision Exercise Short Answer Questions
  1. In the adjoining figure , DeltaABC is a right - angled triangle , righ...

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  2. If sin(A-B)=1/2,""""cos(A+B)=1/2, 0o<A+Blt=90o,""""A > B , find A and ...

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  3. Find the value of sin30^(@) geometrically.

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  4. Find the value of sin60^(@) geometrically.

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  5. Prove that sqrt(sec^(2)theta + cosec^(2)theta) = tantheta + cottheta.

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  6. Prove that : sqrt((1+costheta)/(1-costheta))="cosec"theta+cottheta

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  7. sqrt((1+sintheta)/(1-sintheta))+sqrt((1-sintheta)/(1+sintheta)) is equ...

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  8. Prove that : tan^(2)theta-sin^(2)theta=tan^(2)thetasin^(2)theta

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  9. Prove that : (tanA+sinA)/(tanA-sinA)=(secA+1)/(secA-1)

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  10. Prove that : sin^(2)Acos^(2)B-cos^(2)Asin^(2)B=sin^(2)A-sin^(2)B

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  11. Prove that : sin^(2)theta+cos^(4)theta=cos^(2)theta+sin^(4)theta

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  12. Prove that : sin^(2)theta+(1)/(1+tan^(2)theta)=1

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  13. Prove that : (1-costheta)(1+costheta)(1+cot^(2)theta)=1

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  14. Prove that : (tan^(2)theta)/(1+tan^(2)theta)+(cot^(2)theta)/(1+cot^...

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  15. If tan3A=cot(A-10^(@)) where 3A is an angle , find A.

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  16. If cos5A=sin(A-30^(@)) where 5A is an acute angle , find A.

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  17. Show that : (cot(90^(@)-theta)*sin(90^(@)-theta))/(sintheta)+(cot50^...

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  18. The value of (cos(90^0-theta)sec(90^0-theta)tantheta)/(cos e c(90^0-t...

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  19. Show that : cos15^(@)cos35^(@)"cosec" 55^(@)sin30^(@)"cosec"75^(@)=...

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  20. Express cos70^(@)+sin70^(@)+tan65^(@) in terms of trigonometric ratio...

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