# Trigonometry Part 1(Solution): Advance math series 2000 most important questions.

## Trigonometry Part 1(Solution): Advance math series 2000 most important questions.

11°15’

### Solution 2. (c)

Two angles = A and B where A > B.

### Solution 6. (a)

Let No. of terms in 1 + 5 + 9 + ….. + 89 = n

∴ a + (n – 1) d = tn  ;⇒ 1+(b-1)4 = 89  ;⇒ (n – 1)4 = 89 – 1 = 88  ;⇒ n – 1 = 22  ;⇒ n = 23

Now,

### Solution 8. (b)

Maximum value of

### Solution 13. (b)

XZ – YZ = 2 …………(i)

⇒ XY2 + YZ2 = XZ

⇒

⇒ 24 = (XZ – YZ)(XZ + YZ) ; ⇒ 24 = (XZ – YZ)(XZ + YZ) ;

⇒ XZ + YZ = 12 ……..(ii)

2 X Z = 14 ⇒ XZ = 7 ;

### Solution 17. (b)

⇒ AB = 2k, BC = k

### Solution 29.

When sign is + ve then take greater value of sign is – ve then take-vevalue .

### Solution 31.

A + B = 450

tan (A + B) = tan 450

=

⇒tan A + tan B = 1 – tan A. tan B ;

⇒ tan A + tan B + tan A. tan B = 1

⇒ 1 + tan A + tan B + tan A. tan B = 1 + 1;               ⇒ (1 + tan A) + tan B(1 + tan A) = 2

⇒ (1 + tan A)(1 + tan B) = 2

### Solution 33.

Sin 100. Sin 500. Sin 700

Sin (900 – 800) sin (900 – 400). Sin (900 – 200) = cos 20. Cos 40. Cos 80