#### Term 3 Trigonometry Book Back Questions

9th Standard

Reg.No. :
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Maths

Time : 00:45:00 Hrs
Total Marks : 30
5 x 1 = 5
1. if sin 300 = x and cos 600 = y, then x2  + y2 is

(a)

$\frac { 1 }{ 2 }$

(b)

0

(c)

sin90°

(d)

cos90°

2. The value of 2tan30° tan60° is

(a)

1

(b)

2

(c)

$2\sqrt { 3 }$

(d)

6

3. The value of tan1°.tan2°.tan3°...tan89° is

(a)

0

(b)

1

(c)

2

(d)

$\frac { \sqrt { 3 } }{ 2 }$

4. Given that sin $\alpha$ = $\frac { 1 }{ 2 }$ and cos $\beta$ = $\frac { 1 }{ 2 }$, then the value of $\alpha$ + $\beta$ is

(a)

00

(b)

900

(c)

300

(d)

600

5. The value of $\frac { sin{ 29 }^{ 0 }31' }{ cos{ 60 }^{ 0 }29' }$ is

(a)

0

(b)

2

(c)

1

(d)

-1

6. 4 x 2 = 8
7. If cos A = $\frac { 2x }{ 1+{ x }^{ 2 } }$ then find the values of sinA and tanA in terms of x.

8. If sin $\theta$  = $\frac { a }{ \sqrt { { a }^{ 2 }+{ b }^{ 2 } } }$ then show that b sin $\theta$ = a cos $\theta$

9. If 3cot A = 2 , then find the value of = $\frac { 4sinA-3cosA }{ 2sinA+3cosA }$

10. Find the six trigo'nometric ratios of the angle 0 using the diagram

11. 4 x 3 = 12
12. For the measures in the figure, compute sine, cosine and tangent ratios of the angle $\theta$

13. Evaluate: (i) $\frac { sin49° }{ cos41° }$ (ii) $\frac { sec63° }{ cosec27° }$

14. i) If cosecA = sec340, find A (ii) If tanB = cot 470, find B.

15. Find the area of the right angled triangle with hypotenuse 5cm and one of the acute angle is 48030'

16. 1 x 5 = 5
17. Find the values of the following:
(i) (cos00 + sin450 + sin300)(sin900 - cos450 + cos600)
(ii) tan2600 - 2tan2450 - cot2300 +2sin2300$\frac { 3 }{ 4 }$ cosec2 450