If `y = sin^(4)x + cos^(4)x ` then `(y_(4)(0))/8` is equal to

If y=1+4sin^2 x cos^(2) x , then

If y = e ^(-x) cos x then y _(4) =

If y=128 sin ^(3) x cos ^(4) x ,then find (d^(2)y)/dx^(2)

If x sin y = 3 sin y + 4 cos y , then (dy)/(dx) =

If y= ( sin^(4) x - cos^(4) x + sin^(2) x cos^(2) x )/( sin^(4) x + cos^(4) x + sin^(2) x cos^(2) x) , x in ( 0, (pi)/(2) ) , then

If x = a cos^(4)t , y = b sin^(4)t then (dy)/(dx) at t = (3pi)/4 is

If y =a cos 2x +b sin 2x then y _(2) + 4y =

If the angle between the circlex x^(2) + y^(2) - 2x - 4y + c = 0 and x^(2) + y^(2) - 4x - 2y + 4 = 0 is 60^(@) , then c is equal to

If x = a cos^4 t , y = b sin^4 t then (dy)/(dx) at t= pi/4 is