Question

(4r)²=(a-2r)²+(a-2r)² qual valor de r? Tenho a resposta porém não sei resolver.

Answer 1

(4r)²=(a-2r)²+(a-2r)²

(4r)²=2(a-2r)²

16r²=2(a-2r)²

16r²=2a²-8ar+8r²

8r²+8ar-2a²=0

r'=[-8a+ √(64a²+64a²)]/16

r'=[-8a+8a√2]/16 =-a/2 +a√2/2 =(√2-1)a/2

r''=[-8a- √(64a²+64a²)]/16

=[-8a-8a√2]/16 =-a/2 -a√2/2 =-(√2+1)a/2