Find the value of K so that 4x+Ky=15 makes an angle of 60° with y-axis​

Can someone me and plz do the problem

X/y + 4y/x divided by x/y - 2y/x explain as in depth as you can how you simplfied the fractions. i don't know where to start on this : /

Consider the sequence below. 3 , 1 , 1/3 , 1/9 , select the explicit function which defines the sequence.