if tan theta is 4, what is sec theta?

$${\left({\mathtt{1}}{\mathtt{\,\small\textbf+\,}}{{\mathtt{4}}}^{{\mathtt{2}}}\right)}^{\left({\frac{{\mathtt{1}}}{{\mathtt{2}}}}\right)} = {{\mathtt{17}}}^{\left({\frac{{\mathtt{1}}}{{\mathtt{2}}}}\right)}$$

If tanΘ = 4......then (x,y) equals either (1,4)  or (-1, -4)

And r  = √[x² + y²]  = √17  ..... so secΘ =  r/x =  ±(√17)/1  = ±(√17)