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Mathematics
Mathematics
Problem
d
20
y
d
x
20
(
2
cos
x
cos
3
x
)
\frac{d^{20}y}{dx^{20}}(2 \cos x \cos 3x)
d
x
20
d
20
y
(
2
cos
x
cos
3
x
)
is equal to (a)
2
20
(
cos
2
x
−
2
20
cos
3
x
)
2^{20}(\cos 2x - 2^{20} \cos 3x)
2
20
(
cos
2
x
−
2
20
cos
3
x
)
(b)
2
20
(
cos
2
x
+
2
20
cos
4
x
)
2^{20}(\cos 2x + 2^{20} \cos 4x)
2
20
(
cos
2
x
+
2
20
cos
4
x
)
(c)
2
20
(
sin
2
x
+
2
20
sin
4
x
)
2^{20}(\sin 2x + 2^{20} \sin 4x)
2
20
(
sin
2
x
+
2
20
sin
4
x
)
(d)
2
20
(
sin
2
x
−
2
20
sin
4
x
)
2^{20}(\sin 2x - 2^{20} \sin 4x)
2
20
(
sin
2
x
−
2
20
sin
4
x
)
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