# 1-3/4 sin2 2A=

1.  1/4(1+3 cos2 2A)

2.  1/4(1- 3 cos2 2A)

3.  1/4(1+2 cos2 3A)

4.  1/4(1- 2cos2 3A)

4

1/4(1+3 cos2 2A)

Explanation :
No Explanation available for this question

# If the circles x2+y2+2ax+4ay-3a2=0 and x2+y2-8ax-6ay+7a2=0 touch each other externally, the point of contact is

1.  (a, a)

2.  (0, a)

3.  (a, 0)

4.  (-a, 0)

4

(a, 0)

Explanation :
No Explanation available for this question

# The condition that the circles x2+y2+2ax+c=0, x2+y2+2by+c=0 may touch each other is

1.  1/a+1/b=1/c

2.  1/a+1/b=1/c2

3.  1/a2+1/b2=1/c

4.  1/a2+1/b2=1/c2

4

1/a2+1/b2=1/c

Explanation :
No Explanation available for this question

# The condition that the circles x2+y2+2ax+2by+c=0, x2+y2+2bx+2ay+c=0 to touch each other is

1.  (a+b)2=c

2.  (a+b)2=2c

3.  (a-b)2=c

4.  (a-b)2=2c

4

(a+b)2=2c

Explanation :
No Explanation available for this question

# sin 10 θ+sin 2θ=

1.  2 sin 6θ cos 4θ

2.  2 cos 6θ cos θ

3.  2 cos 4θ sin 2θ

4.  2 sin 4θ cos 2θ

4

2 sin 6θ cos 4θ

Explanation :
No Explanation available for this question

# The two circles x2+y2=a2, x2+y2=c2(c>0) touch each other if

1.    a=2c a) a=2c b) |a|=2c c) 2|a|=c d) |a|=c

2.   |a|=2c

3.  2|a|=c

4.  |a|=c

4

|a|=c

Explanation :
No Explanation available for this question

# The equation of the circle with centre (-1, 1) and touching the circle x2+y2-4x+6y-3=0 externally is

1.  x2+y2+2x-2y+1=0

2.  2x2+2y2+12x-2y+1=0

3.  x2+y2+2x+12y-11=0

4.  3x2+3y2+20x-21y+1=0

4

x2+y2+2x-2y+1=0

Explanation :
No Explanation available for this question

# sin 4θ. Sin 6θ=

1.  2[cos 2θ- cos 10θ]

2.  2[cos 2θ+ cos 10θ]

3.  2[sin 2θ- cos 10θ]

4.  2[sin 2θ+cos 10θ]

4

2[cos 2θ- cos 10θ]

Explanation :
No Explanation available for this question

# sin 6θ(2cos2θ-1)=

1.  1/2(sin 8θ+sin 4θ)

2.   1/2(sin 8θ-sin 4θ)

3.  1/2(cos 8θ+cos 4θ)

4.  1/2(cos 8θ-cos 4θ)

4

1/2(sin 8θ+sin 4θ)

Explanation :
No Explanation available for this question

1.  0

2.  1

3.  2

4.  3

4