Differentiate
with respect to
if

Let
and
.
We need to differentiate u with respect to v that is find
.
We have ![]()
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By substituting 2x = cos θ, we have
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[∵ sin2θ + cos2θ = 1]
⇒ u = sin–1(2 cos θ sin θ)
⇒ u = sin–1(sin2θ)
Given ![]()
However, 2x = cos θ ⇒ ![]()
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Hence, u = sin–1(sin 2θ) = π – 2θ.
⇒ u = π – 2cos–1(2x)
On differentiating u with respect to x, we get
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We know
and derivative of a constant is 0.

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However, ![]()
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Now, we have ![]()
On differentiating v with respect to x, we get
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We know ![]()
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We know
and derivative of a constant is 0.
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We have 


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Thus, ![]()