I can’t copy the exact “book-back” NCERT questions word-for-word (copyright), but I can give you a high-yield “Important Concepts + NCERT-style Important Questions” set for Class 11 Maths, Chapter 3 (Trigonometric Functions). If you upload a photo of the back-exercise page, I can also solve those exact questions.

Chapter 3: Must-know concepts (quick list)

• Degree–radian conversion, angle measure on circle, arc length idea
• Trig functions as coordinates on unit circle; signs in quadrants
• Standard values at $0,\ \pi/6,\ \pi/4,\ \pi/3,\ \pi/2$ etc.
• Periodicity and graphs of $\sin,\cos,\tan,\cot,\sec,\csc$
• Domain & range; maxima/minima of basic trig expressions
• Identities: Pythagorean, reciprocal, quotient
• Compound angle: $\sin(A\pm B),\ \cos(A\pm B),\ \tan(A\pm B)$
• Double angle + simple transformations
• General solutions of trig equations

Formula sheet (most used)

• $\sin^2x+\cos^2x=1$, $1+\tan^2x=\sec^2x$, $1+\cot^2x=\csc^2x$
• $\sin(A\pm B)=\sin A\cos B\pm \cos A\sin B$
• $\cos(A\pm B)=\cos A\cos B\mp \sin A\sin B$
• $\tan(A\pm B)=\dfrac{\tan A\pm \tan B}{1\mp \tan A\tan B}$
• $\sin 2x=2\sin x\cos x$
• $\cos 2x=\cos^2x-\sin^2x=1-2\sin^2x=2\cos^2x-1$
• General solutions:
  • $\sin x=\sin a \Rightarrow x=n\pi+(-1)^n a$
  • $\cos x=\cos a \Rightarrow x=2n\pi\pm a$
  • $\tan x=\tan a \Rightarrow x=n\pi+a$ where $n\in\mathbb Z$

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Important NCERT-style questions (original practice set)

A) Basic / 1-mark–2-mark

1. Convert: (i) $150^\circ$ to radians (ii) $\dfrac{7\pi}{6}$ to degrees.
2. Find $\sin\left(\dfrac{11\pi}{6}\right),\ \cos\left(\dfrac{7\pi}{4}\right),\ \tan\left(\dfrac{5\pi}{3}\right)$.
3. If $\sin\theta=\dfrac{3}{5}$ and $\theta$ is in quadrant II, find $\cos\theta,\tan\theta$.
4. State domain and range of $y=\sin x$ and $y=\sec x$.
5. Find the period of (i) $\sin(3x)$ (ii) $\cos\left(\dfrac{x}{2}\right)$ (iii) $\tan(2x-\pi/6)$.

B) Identities (very important)

6. Prove: $\dfrac{1-\sin x}{\cos x}=\sec x-\tan x$.
7. Prove: $(\sec x-\tan x)(\sec x+\tan x)=1$.
8. Simplify: $\dfrac{\sin x+\sin 3x}{\cos x+\cos 3x}$.
9. Prove: $\dfrac{\cos x}{1-\sin x}=\sec x+\tan x$.
10. If $\sin x+\cos x=\sqrt2\cos\left(x-\dfrac{\pi}{4}\right)$, use it to find the maximum value of $\sin x+\cos x$.

C) Compound angle / double angle (high frequency)

11. Evaluate exactly: $\sin 75^\circ,\ \cos 15^\circ,\ \tan 105^\circ$.
12. Express $\sin(x+\pi/3)$ in terms of $\sin x,\cos x$.
13. If $\tan A=\dfrac{1}{2}$ and $\tan B=\dfrac{1}{3}$, find $\tan(A+B)$.
14. Prove: $\sin(x+y)\sin(x-y)=\sin^2x-\sin^2y$.
15. Using double-angle, show that $1+\cos 2x=2\cos^2x$.

D) Graph / domain-range based

16. Find domain and range of $y=2\sin(3x-\pi/4)$.
17. Find all $x\in[0,2\pi]$ where $\cos x\ge 0$.
18. For $y=\tan x$, write the interval(s) in $[0,2\pi]$ where it is increasing and where it is undefined.

E) Trigonometric equations (most asked)

19. Solve in $[0,2\pi]$: $2\sin x=\sqrt3$.
20. Solve in $[0,2\pi]$: $\cos 2x=\dfrac{1}{2}$.
21. Solve (general solution): $\tan x=1$.
22. Solve (general solution): $\sin(2x)=\sin\left(\dfrac{\pi}{3}\right)$.
23. Solve in $[0,2\pi]$: $\sin x+\cos x=0$.
24. Solve in $[0,2\pi]$: $\sec x=2$.
25. Solve (general solution): $\cos x=\cos\left(\dfrac{\pi}{6}\right)$.

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If you tell me which exercise you mean (e.g., “Miscellaneous Exercise” or a specific exercise number), or upload a photo of the “book back” questions, I’ll mark the most important ones and give you step-by-step solutions.