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If x=15^(@), evaluate : 8sin2xcos4xsin6x...

If `x=15^(@)`, evaluate : `8sin2xcos4xsin6x`

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To evaluate the expression \( 8 \sin 2x \cos 4x \sin 6x \) given \( x = 15^\circ \), we can follow these steps: ### Step 1: Substitute the value of \( x \) We start by substituting \( x = 15^\circ \) into the expression. \[ 2x = 2 \times 15^\circ = 30^\circ \] \[ 4x = 4 \times 15^\circ = 60^\circ \] \[ 6x = 6 \times 15^\circ = 90^\circ \] Now we rewrite the expression with these values: \[ 8 \sin 30^\circ \cos 60^\circ \sin 90^\circ \] ### Step 2: Use trigonometric values Next, we use the known values of the trigonometric functions: \[ \sin 30^\circ = \frac{1}{2} \] \[ \cos 60^\circ = \frac{1}{2} \] \[ \sin 90^\circ = 1 \] ### Step 3: Substitute the trigonometric values into the expression Now we substitute these values back into the expression: \[ 8 \times \frac{1}{2} \times \frac{1}{2} \times 1 \] ### Step 4: Simplify the expression Now we simplify the expression step by step: \[ = 8 \times \frac{1}{2} \times \frac{1}{2} \times 1 \] \[ = 8 \times \frac{1}{4} \] \[ = 2 \] ### Final Answer Thus, the final answer is: \[ \boxed{2} \] ---
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ICSE-TRIGONOMETRICAL RATIOS OF STANDARD ANGLES-EXERCISE 23(C)
  1. If x=15^(@), evaluate : 8sin2xcos4xsin6x

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  2. Solve the following equations for A, if : 2sinA=1

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  3. Solve the following equations for A, if : 2cos2A=1

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  4. Solve the following equations for A, if : sin3A=sqrt(3)/2

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  5. Solve the following equations for A, if : sec2A=2

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  6. Solve the following equations for A, if : sqrt(3)tanA=1

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  7. Solve the following equations for A, if : tan3A=1

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  8. Solve the following equations for A, if : 2sin3A=1

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  9. Solve the following equations for A, if : sqrt(3)cot2A=1

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  10. Calculate the value of A, if : (sinA-1)(2cosA-1)=0

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  11. Calculate the value of A, if : (tanA-1)(cosec3A-1)=0

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  12. Calculate the value of A, if : (sec2A-1)(cosec3A-1)=0

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  13. Calculate the value of A, if : cos3A.(2sin2A-1)=0

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  14. Calculate the value of A, if : (cosec2A-2)(cot3A-1)=0

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  15. If 2sinx^(@)-1=0 and x^(@) is an acute angle, find: (i) bsinx^(@)" ...

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  16. If 4cos^(2)x^(@)-1=0 and 0 le x^(@) le 90^(@), find : x^(@)

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  17. If 4cos^(2)x^(@)-1=0 and 0 le x^(@) le 90^(@), find : sin^(2)x^(@)+c...

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  18. If 4cos^(2)x^(@)-1=0 and 0 le x^(@) le 90^(@), find : 1/(cos^(2)x^(@...

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  19. If 4sin^(2)theta-1=0 and angle theta is less than 90^(@), find the val...

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  20. If sin3A=1 and 0 le A le 90^(@), find : sin A

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  21. If sin3A=1 and 0 le A le 90^(@), find : cos 2A

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