SSC CGL 2023 PYQ — Question 71

The correct answer is option 4 i.e. cos²$\theta$ - sin² $\theta$ - 1

As we know

The identity in the trigonometry

sin² $\theta$ + cos² $\theta$ = 1

 1 - sin² $\theta$ = cos² $\theta$ [ Option 3 is correct identity]

sec² $\theta$  - tan² $\theta$ = 1 

 1 + tan² $\theta$ = sec² $\theta$ [ Option 2 is correct identity]

cosec²  $\theta$ - cot² $\theta$ = 1

 1 + cot² $\theta$ = cosec²  $\theta$ [ Option 1 is correct identity]

Hence, Option 4 i.e. cos²$\theta$ - sin² $\theta$ - 1 is not correct identity