Evaluate (i) sin 30 degree + cos 30 degree. (ii) tan 60 degree cot 60 degree

Answer

D

Explanation

Given, `f(x)=(1+b^(2))x^(2)+2bx+1`
`=(1+b^(2))(x+(b)/(1+b^(2)))^(2)+1-(b^(2))/(1+b^(2))`
m(b) = minimum value of `f(x)=(1)/(1+b^(2))` is positive and m(b) varies from 1 to 0, so range = (0, 1]