Question

If cos $20^\circ$ - sin equal to 20$20^\circ$ = p, then cos 40$20^\circ$ is

• A. $p^2\sqrt{2-p^2}$
• B. $p\sqrt{2-p^2}$
• C. $p+\sqrt{2-p^2}$
• D. $p-\sqrt{2-p^2}$

Answer 1

Answer: (B)

Correct answer is (b) $p\sqrt{2-p^2}$