Question

If f x is equal to cos square x + 6 square x then

Answer 1

x+1/x>=2. Simply, taking x= cos^2 x, the minimum value of cos^2x + sec^2x is 2. ... (a+ b)/2 is greater than or equal to sqrt(ab) . ... ( cos^2 x+sec^2 x)/2>=square root of (sec^2