SSC 2015 paper questions
Q11) If 0° < θ < 90° then the value of sin θ + cos θ is 1) equal to 1 2) greater than 1 3) less than 1 4) equal to 2 Let y = sin θ + cos θ y2 = sin2 θ + cos2θ + 2 sinθ.cosθ = 1 + 2sinθcosθ For 0° < θ < 90°,sinθ < 1,cosθ < 1 2 sin θ cos θ < 1 y2 = 2 y < √2 Hence, option 3. Q12) Maximum value of sin8θ + cos14θ for all real values of θ is 1) 1 2) 0 3) 1.414 4) 0.707 sin8θ + cos14θ = sin8θ + (1 - sin2θ)7 Maximum value of sin2θ = 1 So, maximum value of sin8θ + (1 - sin2θ)7 = 1 + 0 = 1 Hence, option 1. Read More:Trigonometric Identities 1) -1 2) 0 3) 1 4) 2 for all integral values of x. Hence, option 2. Q14) In a right angled triangle XYZ right angled at Y, if then sec x + tan x is Hence, option 2. Q15) If cos x + sec x = 2 then what is the value of cos(n+1) x + sec(n+1)x where n is a positive integer? 1) 2(n+1) 2) 2(n-1) 3) 2n 4) 2 If then So, cos(n+1) x + sec(n+1)x = 2 Hence, option 4. Q16) Consider the following statements A) tan θ increases faster than sin θ as θ increases. B) The value of sin θ + cos θ is always greater than 1. Which of the statements given above is/are correct? 1) Only A 2) Only B 3) Both A and B 4) Neither A nor B Statement A is correct as tan θ increases faster than sin θ as θ increases. Statement B is not correct as sin θ + cos θ can even be equal to 1. Hence, option 1. Hence, option 3. Q18) If cos x + cos2x = 1 then the numerical value of sin12x + 3sin10x + 3sin8x + sin6x - 1 is 1) 1 2) 0 3) -1 4) 2 cos x + cos2x = 1 cos x = 1 - cos2x = sin2x On cubing both sides, cos x + cos2x = 1 (cos x + cos2x)3 = 1 cos6x + 3cos5x + 3cos4x + cos3x = 1 Put cos x = sin2x sin12x + 3sin10x + 3sin8x + sin6x = 1 sin12x + 3sin10x + 3sin8x + sin6x - 1 = 0 Hence, option 2. |
- Trigonometry
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