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Rohit Jha

Jul 15, 2014



Kishore Kumar

Feb 2, 2014



Rohit Jha

Jul 15, 2014

#### 4. sin 600 * tan (-690) + sec 840 * cot(-945)



Solution:
Given : Sin 600° * Tan (-690°) + Sec 840° * Cot(-945°)
= Sin 600°  x -Tan 690° + Sec 840°  x -Cot 945&d...

P Murali Krishna

May 3, 2015

####  Find the value of   cos(π/5) cos(2π/5) cos(4π/5) cos(8π/5)



Given cos(π/5) cos(2π/5) cos(4π/5) cos(8π/5)   [ multiply and divide by 2sin(π/5) ]

⇒ 2sin(π/5)cos(π/5) cos(2π/5) cos(4π/5) cos(8π...

Rejitha Krishnan RG

Aug 23, 2014

#### prove that: cosπ/7*cos2π/7*cos4π/7=-1/8



Sol:
Given  cosπ / 7 cos2π/ 7 cos4π/ 7  [ Multiply and divided by 2 Sin π / 7 ]

⇒ 2Sin π / 7 cosπ / 7 cos2π/ 7 cos4π/ 7 / 2 Sin...

Saba Hussain

Jun 7, 2014

#### Urgent!



Sol :
Given that Tan3 x - 3 Tan x = 0

⇒ 3 Tan x - Tan3 X = 0

We know that Tan 3x = (3 Tan x - Tan3 x) / ( 1 - 3 Tan2 x)

Rohit Jha

Jul 15, 2014

#### 2. If tan 35 = x then Prove that       tan 145 - tan 125 /1+ tan 145 * tan 125 = 1-x2/2x



Sol :
Given that Tan 35 = x

⇒ T

Kahan Mehta

Aug 6, 2014

#### If 3sinx - 5cosx = a, then 5sinx + 3cosx is equal to ?



Sol:
Given 3 Sinx - 5 Cosx = a  squearing on both sides

9 Sin2 x + 25 Cos2 x  - 30 Sin x Cos x = a2 ---------------(1)

Let 5 Sin x...

Jahnavi

Jun 18, 2014

#### In a triangle ABC, if  a cosA = b cos B, then it is which type of triangle?



Sol:
Given a cosA = b cos B
2R Sin A Cos A = 2R Sin B Cos B.
2 Sin A Cos A = 2 Sin B Cos B.
Sin 2A = Sin 2B
2A = 2B
A = B.
An isosceles triangle is a triangle wi...

Rejitha Krishnan RG

Sep 11, 2014

#### if y=2sinx /(1+cosx+sinx) then (1-cosx+sinx)/(1+sinx) = a)1+y b)1-y c)1/y d)y



Sol :
Given y = 2sinx /(1+cosx+sinx) rationalize with (1 - cos x + sin x)

⇒ y = 2sin x(1 - cos x + sin x) / (1 + cos x + sinx)(1 - cos x + sin x)

⇒ y = 2sin x(1 ...

Rohit Jha

Jul 15, 2014



Kishore Kumar

Feb 2, 2014



Rohit Jha

Jul 15, 2014

#### 4. sin 600 * tan (-690) + sec 840 * cot(-945)



Solution:
Given : Sin 600° * Tan (-690°) + Sec 840° * Cot(-945°)
= Sin 600°  x -Tan 690° + Sec 840°  x -Cot 945&d...

P Murali Krishna

May 3, 2015

####  Find the value of   cos(π/5) cos(2π/5) cos(4π/5) cos(8π/5)



Given cos(π/5) cos(2π/5) cos(4π/5) cos(8π/5)   [ multiply and divide by 2sin(π/5) ]

⇒ 2sin(π/5)cos(π/5) cos(2π/5) cos(4π/5) cos(8π...

Rejitha Krishnan RG

Aug 23, 2014

#### prove that: cosπ/7*cos2π/7*cos4π/7=-1/8



Sol:
Given  cosπ / 7 cos2π/ 7 cos4π/ 7  [ Multiply and divided by 2 Sin π / 7 ]

⇒ 2Sin π / 7 cosπ / 7 cos2π/ 7 cos4π/ 7 / 2 Sin...

Saba Hussain

Jun 7, 2014

#### Urgent!



Sol :
Given that Tan3 x - 3 Tan x = 0

⇒ 3 Tan x - Tan3 X = 0

We know that Tan 3x = (3 Tan x - Tan3 x) / ( 1 - 3 Tan2 x)

Rohit Jha

Jul 15, 2014

#### 2. If tan 35 = x then Prove that       tan 145 - tan 125 /1+ tan 145 * tan 125 = 1-x2/2x



Sol :
Given that Tan 35 = x

⇒ T

Kahan Mehta

Aug 6, 2014

#### If 3sinx - 5cosx = a, then 5sinx + 3cosx is equal to ?



Sol:
Given 3 Sinx - 5 Cosx = a  squearing on both sides

9 Sin2 x + 25 Cos2 x  - 30 Sin x Cos x = a2 ---------------(1)

Let 5 Sin x...

Jahnavi

Jun 18, 2014

#### In a triangle ABC, if  a cosA = b cos B, then it is which type of triangle?



Sol:
Given a cosA = b cos B
2R Sin A Cos A = 2R Sin B Cos B.
2 Sin A Cos A = 2 Sin B Cos B.
Sin 2A = Sin 2B
2A = 2B
A = B.
An isosceles triangle is a triangle wi...

Rejitha Krishnan RG

Sep 11, 2014

#### if y=2sinx /(1+cosx+sinx) then (1-cosx+sinx)/(1+sinx) = a)1+y b)1-y c)1/y d)y



Sol :
Given y = 2sinx /(1+cosx+sinx) rationalize with (1 - cos x + sin x)

⇒ y = 2sin x(1 - cos x + sin x) / (1 + cos x + sinx)(1 - cos x + sin x)

⇒ y = 2sin x(1 ...

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