O valor de y = (cos a + cos b)² + (sen a - sen b)², para a+b = π/2 é:
a)1/2
b)2
c)0
d)1
e)4
PRECISO DA RESOLUÇÃO!
y = (cos a + cos b)² + (sen a - sen b)²
=cos²a+2cosa.cosb+cos²b+
+sen²a-2sena.senb+sen²b
=sen²a+cos²a+sen²b+cos²b+
+2cosacosb-2senasenb
=1+1+2(cosacosb-senasenb)
=2+2cos(a+b)
=2+2cos(π/2)
=2+2(0)
y=2
Até!
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Verified answer
y = (cos a + cos b)² + (sen a - sen b)²
=cos²a+2cosa.cosb+cos²b+
+sen²a-2sena.senb+sen²b
=sen²a+cos²a+sen²b+cos²b+
+2cosacosb-2senasenb
=1+1+2(cosacosb-senasenb)
=2+2cos(a+b)
=2+2cos(π/2)
=2+2(0)
y=2
Até!