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For any angle theta, state the value of ...

For any angle `theta`, state the value of :
`" "sin^(2)theta+cos^(2)theta`.

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To find the value of \( \sin^2 \theta + \cos^2 \theta \) for any angle \( \theta \), we can follow these steps: ### Step 1: Understand the definitions of sine and cosine In a right triangle, for an angle \( \theta \): - The sine of \( \theta \) is defined as the ratio of the length of the opposite side (perpendicular) to the length of the hypotenuse. - The cosine of \( \theta \) is defined as the ratio of the length of the adjacent side (base) to the length of the hypotenuse. ### Step 2: Write the formulas for sine and cosine Let: - \( P \) = length of the perpendicular side - \( B \) = length of the base side - \( H \) = length of the hypotenuse Then: \[ \sin \theta = \frac{P}{H} \] \[ \cos \theta = \frac{B}{H} \] ### Step 3: Square both sine and cosine Now, we square both sine and cosine: \[ \sin^2 \theta = \left(\frac{P}{H}\right)^2 = \frac{P^2}{H^2} \] \[ \cos^2 \theta = \left(\frac{B}{H}\right)^2 = \frac{B^2}{H^2} \] ### Step 4: Add the squared values Now, we add \( \sin^2 \theta \) and \( \cos^2 \theta \): \[ \sin^2 \theta + \cos^2 \theta = \frac{P^2}{H^2} + \frac{B^2}{H^2} \] ### Step 5: Combine the fractions Since both terms have the same denominator, we can combine them: \[ \sin^2 \theta + \cos^2 \theta = \frac{P^2 + B^2}{H^2} \] ### Step 6: Apply the Pythagorean theorem According to the Pythagorean theorem, we know that: \[ P^2 + B^2 = H^2 \] Substituting this into our equation gives: \[ \sin^2 \theta + \cos^2 \theta = \frac{H^2}{H^2} \] ### Step 7: Simplify the expression Now, simplifying the fraction: \[ \sin^2 \theta + \cos^2 \theta = 1 \] ### Final Answer Thus, for any angle \( \theta \): \[ \sin^2 \theta + \cos^2 \theta = 1 \] ---
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ICSE-TRIGONOMETRICAL RATIOS OF STANDARD ANGLES-EXERCISE 23(A)
  1. If sinx=cosy, then x+y=45^(@), write true or false.

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  2. sectheta.cottheta=cosectheta, write true or false.

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  3. For any angle theta, state the value of : " "sin^(2)theta+cos...

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  4. State for any acute angle theta whether : sintheta increases or decr...

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  5. State for any acute angle theta whether : costheta increases or decr...

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  6. State for any acute angle theta whether : tantheta increases or decr...

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  7. If sqrt(3)=1*732, find (correct to two decimal places) the value of th...

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  8. Evaluate : (cos3A-3cos4A)/(sin3A+2sin4A)," when "A=15^(@).

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  9. Evaluate : (3sin3B+2cos(2B+5^(@)))/(2cos3B-sin(2B-10^(@))), when B...

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  10. Find the value of : sin30^(@)cos30^(@)

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  11. Find the value of : tan30^(@)tan60^(@)

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  12. Find the value of : cos^(2)60^(@)+sin^(2)30^(@)

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  13. Find the value of : cosec^(2)60^(@)-tan^(2)30^(@)

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  14. Find the value of : sin^(2)30^(@)+cos^(2)30^(@)+cot^(2)45^(@)

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  15. Find the value of : cos^(2)60^(@)+sec^(2)30^(@)+tan^(2)45^(@)

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  16. Find the value of : tan^(2)30^(@)+tan^(2)45^(@)+tan^(2)60^(@)

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  17. Find the value of : (tan45^(@))/(cosec30^(@))+(sec60^(@))/(cot45^(@)...

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  18. Find the value of : 3sin^(2)30^(@)+2tan^(2)60^(@)-5cos^(2)45^(@)

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  19. Prove that : sin60^(@)cos30^(@)+cos60^(@).sin30^(@)=1

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  20. Prove that : cos30^(@).cos60^(@)-sin30^(@).sin60^(@)=0

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