|q⟩
Bad Qubits
Play
Quest
Questions
Learn
Playground
☕
← Question Bank
Multiple choice
A variational cost is
E
(
θ
)
=
cos
(
θ
)
E(\theta) = \cos(\theta)
E
(
θ
)
=
cos
(
θ
)
, so its gradient is
d
E
/
d
θ
=
−
sin
(
θ
)
dE/d\theta = -\sin(\theta)
d
E
/
d
θ
=
−
sin
(
θ
)
. At
θ
=
π
/
3
\theta = \pi/3
θ
=
π
/3
, what are
(
E
,
d
E
/
d
θ
)
(E, dE/d\theta)
(
E
,
d
E
/
d
θ
)
?
(
0.5
,
+
3
/
2
≈
+
0.866
)
(0.5, +\sqrt{3}/2 \approx +0.866)
(
0.5
,
+
3
/2
≈
+
0.866
)
(
0.5
,
−
3
/
2
≈
−
0.866
)
(0.5, -\sqrt{3}/2 \approx -0.866)
(
0.5
,
−
3
/2
≈
−
0.866
)
(
3
/
2
≈
0.866
,
−
0.5
)
(\sqrt{3}/2 \approx 0.866, -0.5)
(
3
/2
≈
0.866
,
−
0.5
)
(
0.5
,
−
0.5
)
(0.5, -0.5)
(
0.5
,
−
0.5
)
Check answer