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        <description>Merging man &amp; maths</description>
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        <item>
            <title>Question 4(i-iv), Exercise 9.1</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit09/ex9-1-p4</link>
            <description>Question 4(i-iv), Exercise 9.1

Solutions of Question 4(i-iv) of Exercise 9.1 of Unit 09: Trigonometric Functions. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $y=\sin x+x \cdot \cos x$$f(x)=\sin x+x \cdot \cos x$\begin{align*} f(-x)  = \sin (-x) + (-x)\cdot \cos (-x) \end{align*}$\sin(-x)=-\sin x$$\cos (-x) = \cos x$\begin{align*}
f(x) &amp; = -\sin x - x \cdot \cos x \\
&amp; = -(\sin x + x \cdot …</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Wed, 27 Nov 2024 15:59:11 +0000</pubDate>
        </item>
        <item>
            <title>Question 4(v-viii), Exercise 9.1</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit09/ex9-1-p5</link>
            <description>Question 4(v-viii), Exercise 9.1

Solutions of Question 4(v-viii) of Exercise 9.1 of Unit 09: Trigonometric Functions. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $y=\dfrac{\sin ^{2} x}{x+\tan x}$\[y = \frac{\sin^2 x}{x + \tan x}\]\begin{align*}
y(-x) &amp;= \frac{\big(-\sin x\big)^2}{-x - \tan x} \\
&amp;= \frac{\sin^2 x}{-x - \tan x}\\
&amp; = \frac{\sin^2 x}{-(x + \tan x)}\\
&amp; = -\frac{\sin^2 x}{x +…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Wed, 27 Nov 2024 15:59:12 +0000</pubDate>
        </item>
        <item>
            <title>Question 1,Review Exercise</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit09/re-ex-p1</link>
            <description>Question 1,Review Exercise

Solutions of Question 1 of Review Exercise of Unit 09: Trigonometric Functions. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $\cos \theta=\frac{\sqrt{3}}{2}$$\sin \theta=$$\frac{1}{2}$$-\frac{1}{2}$$\sqrt{3}$$-\frac{2}{\sqrt{3}}$$-\frac{1}{2}$$\tan (-15 \pi)=$$ 0$$-1$$1$$0$$2 \sin \theta+\frac{1}{2}cosec \theta \theta $$\theta=45^{\circ}$$\frac{1}{\sqrt{2}}$$\frac…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Wed, 27 Nov 2024 15:59:18 +0000</pubDate>
        </item>
        <item>
            <title>Question 5(vi-x), Exercise 9.1</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit09/ex9-1-p7</link>
            <description>Question 5(vi-x), Exercise 9.1

Solutions of Question 5(vi-x) of Exercise 9.1 of Unit 09: Trigonometric Functions. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $y=2 \operatorname{Sin} 3 x$$y=3 \operatorname{Cos} x$$y=\operatorname{Cos}^{2} x$$y=\operatorname{Sin}^{2} x$$y=\operatorname{Tan}^{2} x$$y=\operatorname{Sin} \frac{x}{2}$</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Wed, 27 Nov 2024 15:59:14 +0000</pubDate>
        </item>
        <item>
            <title>Question 1, Exercise 9.1</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit09/ex9-1-p1</link>
            <description>Question 1, Exercise 9.1

Solutions of Question 1 of Exercise 9.1 of Unit 09: Trigonometric Functions. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $y=2-2 \operatorname{Cos} \theta$\begin{align*} -1 \leq \operatorname{Cos} \theta \leq 1 \end{align*}$-2$\begin{align*} &amp; 2 \geq -2 \operatorname{Cos} \theta \geq -2 \end{align*}$2$\begin{align*}
 &amp; 4 \geq 2-2 \operatorname{Cos} \theta \geq 0 \\
…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Wed, 27 Nov 2024 15:59:09 +0000</pubDate>
        </item>
        <item>
            <title>Question 2, Exercise 9.1</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit09/ex9-1-p2</link>
            <description>Question 2, Exercise 9.1

Solutions of Question 2 of Exercise 9.1 of Unit 09: Trigonometric Functions. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $y=\dfrac{1}{4+3 \operatorname{Sin} \theta}$\begin{align*} -1 \leq \operatorname{Sin} \theta \leq 1 \end{align*}$3$\begin{align*}  -3 \leq 3 \operatorname{Sin} \theta \leq 3 \end{align*}$4$\begin{align*}
 &amp; 1 \leq 4+3 \operatorname{Sin} \theta \l…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Wed, 27 Nov 2024 15:59:10 +0000</pubDate>
        </item>
        <item>
            <title>Question 5(i-v), Exercise 9.1</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit09/ex9-1-p6</link>
            <description>Question 5(i-v), Exercise 9.1

Solutions of Question 5(i-v) of Exercise 9.1 of Unit 09: Trigonometric Functions. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $y=2 \operatorname{Sin} x$$y=2 \operatorname{Cos} 3 x$$y=2 \operatorname{Tan} 2 x$$\mathrm{y}=\operatorname{Cos} \frac{\mathrm{x}}{2}$</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Wed, 27 Nov 2024 15:59:13 +0000</pubDate>
        </item>
        <item>
            <title>Question 10, Exercise 9.1</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit09/ex9-1-p11</link>
            <description>Question 10, Exercise 9.1

Solutions of Question 10 of Exercise 9.1 of Unit 09: Trigonometric Functions. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $ V(t)=a \operatorname{Sin}(k(t-d))+c$$56 \mathrm{~Hz} A C$$k$</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Wed, 27 Nov 2024 15:59:10 +0000</pubDate>
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