Trigonometry
-  If π sinθ = 1, π cosθ = 1, then the value of  √3tan  2 θ  + 1  is 3 
- 
                        View Hint View Answer Discuss in Forum πsin θ = 1 and πcos θ = 1 ∴ πsin θ = 1 πcos θ 
 ∴ tan θ = 1 = tan 45°
 ⇒ θ = 45°∴ √3tan  2 θ  + 1 3 = √3tan  2 × 45°  + 1 = √3 tan30° + 1 3 Required answer = √3 × 1 + 1 = 1 + 1 = 2 √3 
 Correct Option: Cπsin θ = 1 and πcos θ = 1 ∴ πsin θ = 1 πcos θ 
 ∴ tan θ = 1 = tan 45°
 ⇒ θ = 45°∴ √3tan  2 θ  + 1 3 = √3tan  2 × 45°  + 1 = √3 tan30° + 1 3 Required answer = √3 × 1 + 1 = 1 + 1 = 2 √3 
 
-  Find the value of 1 + 1 . 1 + tan2θ 1 + cot2θ 
- 
                        View Hint View Answer Discuss in Forum Expression = 1 + 1 1 + tan2θ 1 + cot2θ Expression = 1 + 1 sec2θ cosec2θ 
 [ ∵ sec2θ - tan2θ = 1 , cosec2θ - cot2θ = 1 ]
 Expression = cos2θ + sin2θ = 1
 [ ∵ cosθ . secθ = 1 , sinθ . cosecθ = 1 ]
 Correct Option: BExpression = 1 + 1 1 + tan2θ 1 + cot2θ Expression = 1 + 1 sec2θ cosec2θ 
 [ ∵ sec2θ - tan2θ = 1 , cosec2θ - cot2θ = 1 ]
 Expression = cos2θ + sin2θ = 1
 [ ∵ cosθ . secθ = 1 , sinθ . cosecθ = 1 ]
 
-  If tanθ + 1 = 2 , then the value of tan2θ + 1 is equal to : tanθ tan2θ 
- 
                        View Hint View Answer Discuss in Forum tanθ + 1 = 2 tanθ 
 ⇒ tan2θ + 1 = 2tanθ
 ⇒ tan2θ - 2tanθ + 1 = 0
 ⇒ ( tanθ - 1 )2 = 0 ⇒ tanθ - 1 = 0
 ⇒ tanθ = 1∴ tan2θ + 1 = 1 + 1 = 2 tan2θ Correct Option: Ctanθ + 1 = 2 tanθ 
 ⇒ tan2θ + 1 = 2tanθ
 ⇒ tan2θ - 2tanθ + 1 = 0
 ⇒ ( tanθ - 1 )2 = 0 ⇒ tanθ - 1 = 0
 ⇒ tanθ = 1∴ tan2θ + 1 = 1 + 1 = 2 tan2θ 
-  What is the value of (cotθ + cosecθ - 1) ? (cotθ - cosecθ + 1) 
- 
                        View Hint View Answer Discuss in Forum Expression = (cotθ + cosecθ - 1) (cotθ - cosecθ + 1) Expression = cotθ + cosecθ - (cosec2θ - cot2θ) (cotθ - cosecθ + 1) Expression = (cotθ + cosecθ) - (cosecθ - cotθ)(cosecθ + cotθ) (cotθ - cosecθ + 1) Expression = (cotθ + cosecθ)(1 - cosecθ + cotθ) = cotθ + cosecθ (cotθ - cosecθ + 1) Correct Option: AExpression = (cotθ + cosecθ - 1) (cotθ - cosecθ + 1) Expression = cotθ + cosecθ - (cosec2θ - cot2θ) (cotθ - cosecθ + 1) Expression = (cotθ + cosecθ) - (cosecθ - cotθ)(cosecθ + cotθ) (cotθ - cosecθ + 1) Expression = (cotθ + cosecθ)(1 - cosecθ + cotθ) = cotθ + cosecθ (cotθ - cosecθ + 1) 
-  If sinθ × cosθ = 1 .The value of sinθ – cosθ is where 0° < θ < 90° 2 
- 
                        View Hint View Answer Discuss in Forum sinθ. cosθ = 1 2 
 ⇒ 2 sinθ. cosθ = 1
 ⇒ sin2θ = 1 = sin 90°
 ⇒ 2θ = 90°
 ⇒ θ = 45°
 ∴ sinθ – cosθ = sin 45° – cos 45°sin 45° – cos 45° = 1 - 1 = 0 √2 √2 Correct Option: Asinθ. cosθ = 1 2 
 ⇒ 2 sinθ. cosθ = 1
 ⇒ sin2θ = 1 = sin 90°
 ⇒ 2θ = 90°
 ⇒ θ = 45°
 ∴ sinθ – cosθ = sin 45° – cos 45°sin 45° – cos 45° = 1 - 1 = 0 √2 √2 
 
	