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Compute sin 15 ^(@) from the functio...

Compute
`sin 15 ^(@) ` from the functions `60^(@) and 45 ^(@)`

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To compute \( \sin 15^\circ \) using the values of \( \sin 60^\circ \) and \( \sin 45^\circ \), we can use the sine subtraction formula. Here’s how we can do it step by step: ### Step 1: Identify the angles We know that: \[ 15^\circ = 60^\circ - 45^\circ \] ### Step 2: Use the sine subtraction formula The sine subtraction formula states: \[ \sin(a - b) = \sin a \cos b - \cos a \sin b \] In our case, let \( a = 60^\circ \) and \( b = 45^\circ \). Therefore: \[ \sin 15^\circ = \sin(60^\circ - 45^\circ) = \sin 60^\circ \cos 45^\circ - \cos 60^\circ \sin 45^\circ \] ### Step 3: Substitute known values We know the following trigonometric values: - \( \sin 60^\circ = \frac{\sqrt{3}}{2} \) - \( \cos 45^\circ = \frac{1}{\sqrt{2}} \) - \( \cos 60^\circ = \frac{1}{2} \) - \( \sin 45^\circ = \frac{1}{\sqrt{2}} \) Substituting these values into the formula gives: \[ \sin 15^\circ = \left(\frac{\sqrt{3}}{2}\right) \left(\frac{1}{\sqrt{2}}\right) - \left(\frac{1}{2}\right) \left(\frac{1}{\sqrt{2}}\right) \] ### Step 4: Simplify the expression Now, we simplify the expression: \[ \sin 15^\circ = \frac{\sqrt{3}}{2\sqrt{2}} - \frac{1}{2\sqrt{2}} \] To combine these fractions, we need a common denominator: \[ \sin 15^\circ = \frac{\sqrt{3} - 1}{2\sqrt{2}} \] ### Final Result Thus, the value of \( \sin 15^\circ \) is: \[ \sin 15^\circ = \frac{\sqrt{3} - 1}{2\sqrt{2}} \] ---
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ICSE-COMPOUND AND MULTIPLE ANGLES -EXERCISE 5(A)
  1. Compute sin 15 ^(@) from the functions 60^(@) and 45 ^(@)

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  2. Compute cos 345 ^(@) from the functions of 300^(@) and 45 ^(@)

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  3. Compute tan 105^(@) from the functions of 45 ^(@) and 60^(@)

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  4. Compute sin 13 5 ^(@) from the functions of 180^(@) and 45 ^(@)

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  5. Compute cos 195^(@) from the functions of 15 0^(@) and 45 ^(@),

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  6. Compute cosec (13pi//12)

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  7. Simplify be reducing to a single term : sin 3 alpha cos 2 alpha + co...

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  8. Simplify be reducing to a single term : cos 5 theta cos 2 theta - si...

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  9. Simplify by reducing to a single term : sin 22 ^(@) cos 38^(@) + cos...

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  10. Simplify be reducing to a single term : sin 80^(@) cos 20^(@) - cos ...

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  11. Simplify by reducing to a single term : sin (x -y) cos x - cos (x-y)...

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  12. Simplify be reducing to a single term : cos (theta + alpha ) cos ( t...

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  13. Simplify be reducing to a single term : (tan 69^(@) + tan 66^(@))/(1...

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  14. Simplify be reducing to a single term : (tan alpha - tan ( alpha - b...

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  15. Prove that (sin alpha cos beta + cos alpha sin beta) ^(2) + (cos alpha...

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  16. sin (60^(@) + theta) - sin ( 60^(@) - theta ) = sin theta.

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  17. Prove that sin(θ+30°)+cos(θ+60°)= cos θ.

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  18. sin ( 240^(@) + theta) + cos (330^(@) + theta ) = 0

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  19. sin (A - 45 ^(@) ) = (1)/( sqrt2) (sin A - cos A)

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  20. Prove that :cos ((pi)/(3) + x) = ( cos x - sqrt3 sin x )/(2)

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