Question

Find the general solution of $co{s}^{2}x-1=0$

• A. $x=n\pi$
• B. $x=2n\pi +\frac{\pi }{2}$
• C. $x=n\pi +\frac{\pi }{2}$
• D. $x=2n\pi$

Answer 1

The correct option is A

$x=n\pi$

$co{s}^{2}x-1=01-co{s}^{2}x=0si{n}^{2}x=0sinx=0x=n\pi$