Question

calcular o valor de A^2+1/A^2 sabendo que A+1/A=5

Answer 1

$(A+\frac{1}{A})^2=5^2\\ \\ (A+\frac{1}{A})^2=25\\ \\ A^2+(\frac{1}{A})^2+2.A.\frac{1}{A}=25\\ \\ A^2+(\frac{1}{A})^2+2=25\\ \\ \boxed{\boxed{A^2+(\frac{1}{A})^2=23}}$