If $g(x)=\int_0^x \cos 4 t ~d t$, then $g(x+\pi)$ equals
If $g(x)=\int_0^x \cos 4 t ~d t$, then $g(x+\pi)$ equals
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$\frac{g(x)}{g(\pi)}$
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$g(x)+g(\pi)$
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$g(x)-g(\pi)$
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None of these
Solution
$g(x)=\int_0^x \cos 4 t ~d t$
$\Rightarrow g^{\prime}(x)=\cos 4 x \quad \Rightarrow g(x)=\frac{\sin 4 x}{4}+k \quad \Rightarrow g(x)=\frac{\sin 4 x}{4}[\because g(0)=0]$
$g(x+\pi)=g(x)+g(\pi)=g(x)-g(\pi)(\because g(\pi)=0)$
Asked in: JEE Main 2012 (Offline)
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