Solve the equation cosx= -0.4 on the interval 0≤x＜2π.

solve the equation . the minimum value of y=x^3-x on the interval (0,1) urgent!if x satifies the equation sinx+cosx =√2,find the val On what interval is the curve y = x ln(x - 1) concave upward Find all of the solutions of th equation cosx+cos2x=0 1.Find the equation of the tangent to the curve y=x^2,which 微积分Find the interval 1.Express the equation x^3+6*x^2-4*x+5=0 in reduced form and Express the equation x^3+6*x^2-4*x+5=0 in reduced form and d the roots of the equation x2-7x+15=0, 英语翻译If the root of equation(a2-1)x+5|b|-10=0 had innumerabli Find the equation of the tangent line at x=2 for f(x)=√(（4x+