Question

Find the value of y^2+ 1/y^2 if y+ 1/y = √7

Answer 1

Answer:

5

Step-by-step explanation:

Given that,

                   y+1/y=√7

squaring on both sides

(y+1/y)^2=(√7)^2

since we know that

(a+b)^2=a^2+b^2+2ab

so,

y^2+1/y^2+2(y)(1/y)=7

y^2+1/y^2+2(1)=7

y^2+1/y^2=7-2

=>y^2+1/y^2=5

Hope this would be helpful for you