If √5 cosx + √15sinx = 0, for 0° < x < 360°, find the values of x.
30° and 150°
150° and 210°
150° and 330°
210° and 330°
Correct answer is C
√5 cosx + √15sinx = 0;
√5 (cosx + √3sinx) = 0
cosx = -sinx√3; \(\frac{sinx}{cos}\) = \(\frac{-1}{√3}\)
tanx = \(\frac{-1}{√3}\); x = 150° or 330°
120
80
56
30
Correct answer is D
The required committee can be formed in
(a boy and a girl are already part of the committee so we need two more boys and a girl).
\(^{5}C_{2}\) * \(^{3}C_{1}\) = \(\frac{5 * 4*3*2*1}{3* 2 * 2*1}\) * \(\frac{ 3* 2* 1}{ 2 * 1}\)
10 * 3 = 30ways.
292
272
192
172
Correct answer is C
Using the sum of an AP, S\(_n\) = \(\fra{n}{2}\) [ 2a + (n - 1)d]
S\(_3\) = \(\fra{3}{2}\) [ 2a + (3 - 1)d]
18 = \(\fra{3}{2}\) [ 2a + 2d]
2a + 2d = 12
a = 4
2(4) + 2d = 18 --> 8 + 2d = 12
2d = 4; d = 2
a = 4: a + d
= 4 + 2 = 6
a + 2d = 4 + 2]2]
= 8
product of the terms = 4 * 6 * 8 = 192
\(\frac{48}{65}\)
\(\frac{13}{15}\)
\(\frac{-33}{65}\)
\(\frac{-48}{65}\)
Correct answer is C
From Pythagoras' theorem
when sin x = \(\frac{12}{13}\), cos x = \(\frac{5}{13}\)
Using cos (x + y) = cosx cosy - sinxsiny
\(\frac{5}{13}\) * \(\frac{3}{5}\) - \(\frac{12}{13}\) * \(\frac{4}{5}\)
= \(\frac{-33}{65}\)
If ( 1- 2x)\(^4\) = 1 + px + qx\(^2\) - 32x\(^3\) + 16\(^4\), find the value of (q - p)
-32
-16
16
32
Correct answer is D
( 1- 2x)\(^4\) = 1 + px + qx\(^2\) - 32x\(^3\) + 16\(^4\)
compared with: 1 - 8x + 24x\(^2\) - 32x\(^3\) + 16\(^4\)
q = 24 and p = -8
(q - p) = 24 - [-8] = 32