If M = x cos A + y sin A and N = x sin A - y cos A, then M² + N² is :

1. x² - y²

2. y² - x²

3. x² + y²

4. (x + y)²

If sin 2x = 2 sin 45° cos 45°; the value of x is :

1. 45°

2. 90°

3. 30°

4. 60°

For acute angle θ, sec²θ = 1 - tan²θ

Assertion(A): sec²θ = 1 - tan²θ is not a trigonometric identity.

Reason(R): For an acute angle θ, the trigonometric equation is an identity, if it is satisfied for every value of angle θ.

1. A is true, R is false.

2. A is false, R is true.

3. Both A and R are true and R is correct reason for A.

4. Both A and R are true and R is incorrect reason for A.