If `2x+3y=4` , find the maximum or minimum value of xy.

If 'x' be real, find the maximum and minimum value of : y=(x+2)/(2x^(2)+3x+6)

If y = cos^2(45^@+x)+(sin x - cos x)^2 , then find the maximum and minimum value of y.

Show that the function 2x^(3)+3x^(2)-36x+10 has a maximum value at x=-3 and a minimum value at x=2 , also find the maximum and minimum values of the function.

Find the maximum and minimum value of f(x)=3cosx+4sinx

Let x,y in R , then find the maximum and minimum values of expression (x^(2)+y^(2))/(x^(2)+xy+4y^(2)) .

Let x,y in R , then find the maximum and minimum values of expression (x^(2)+y^(2))/(x^(2)+xy+4y^(2)) .

Let x,y in R , then find the maximum and minimum values of expression (x^(2)+y^(2))/(x^(2)+xy+4y^(2)) .

Find maximum & minimum value of 3 sin x-4 cosx

If 7/12xy=21 , then find the minimum value of 5(x+y) .

If x-2y=4 the minimum value of xy is