\frac{9tan^{2}\theta +4cot^{2}\theta }{2}\geq \sqrt{36tan^{2}\theta cot^{2}\theta}
9tan^{2}\theta +4cot^{2}\theta \geq 12
The least value of 9tan2∂ +4cot2∂ is
a) 13
b)5
c) 0
d) none of these
ans. d
\frac{9tan^{2}\theta +4cot^{2}\theta }{2}\geq \sqrt{36tan^{2}\theta cot^{2}\theta}
9tan^{2}\theta +4cot^{2}\theta \geq 12
The problem with tushar's soln is that the part inside bracket is never zero!