Write the least value of cos
Question:
Write the least value of cos2 x + sec2 x.
Solution:
We know:
cos x can take the minimum value of
$\cos ^{2} x+\sec ^{2} x$$=\frac{\cos ^{4} x+1}{\cos ^{2} x}$
$=\frac{(-1)^{4}+1}{(-1)^{2}}$
= 2