Question

pĺease help me

if a-1/a=4,find the value of a×a+1/a×a

please........
..

Answer 1

a - 1/a = 4

To find

a × a + 1/a × a

=> a² + 1/a² = ??

Now, we know that (a - b)² = a² + b² - 2ab

Let's square both the sides,

(a - 1/a)² = (4)²

=> a² + (1/a)² - 2(1/a)(a) = 16

=> a² + 1/a² - 2 = 16

=> a² + 1/a² = 16 + 2

=> a² + 1/a² = 18

=> a × a + 1/(a × a) = 18


Hope it helps dear friend ☺️

Answer 2

$\textbf{\huge{ANSWER:}}$

Given:

$a - \frac{1}{a} = 4$

To find:

${a}^{2} + { \frac{1}{a} }^{2}$

Method:

Identity used:
${(x - y)^{2} = x^{2} + y^{2} - 2xy$

${(a - \frac{1}{a} )}^{2} = {4}^{2} \\ \\ = > {a}^{2} + { \frac{1}{a} }^{2} - 2 = 16 \\ \\ = > {a}^{2} + { \frac{1}{a} }^{2} = 18$

The answer is 18.

Hope my answer Helps!! :)