What is the value of positive square root of $$69+28\sqrt{5}$$ ?
Let $$x=69+28\sqrt5$$
=> $$x=69+2(2)(7)(\sqrt{5})$$
=> $$x=(49)+(20)+2(7)(2\sqrt5)$$
=> $$x=(7)^2+(2\sqrt5)^2+2(7)(2\sqrt5)$$
=> $$x=(7+2\sqrt5)^2$$
=> Positive square root of $$x=7+2\sqrt5$$
=> Ans - (A)
Create a FREE account and get:
Detailed syllabus & Topic-wise Weightage
By proceeding you agree to create your account
Free CAT Syllabus PDF will be sent to your email address soon !!!
