# Kewal

Most popular questions and responses by Kewal-
## Trigonometry

If A + B + C = 180°, Prove that Cos²A + Cos²B + Cos²C = 1-2cosAcosBcosC

*asked on February 10, 2012* -
## Trigonometry

Prove that cos(A+B) + sin(A-B) = 2sin(45°+A)cos(45°+B)

*asked on December 31, 2011* -
## Trigonometry

If sinA + sinB = a and cosA + cosB = b, find the value of tanA-B/2

*asked on January 9, 2012* -
## Trigonometry

Prove that 1-cosA+cosB-cos(A+B)/1+cosA-cosB-cos(A+B) = tanA/2cotA/2

*asked on January 4, 2012* -
## Trigonometry

Prove that sin(A-B)/cosAcosB + sin(B-C)/cosBcosC + sin(C-A)/cosCcosA = 0

*asked on December 30, 2011* -
## Trigonometry

IfA=340°, prove that 2sinA/2 = -(v1+sinA) + (v1-sinA)

*asked on January 12, 2012* -
## Trigonometry

Prove that cos(A+B)cosC - cos(B+C)cosA = sinBsin(C-A)

*asked on December 30, 2011* -
## Trigonometry

cos²a + cos²(a+120°) + cos(a-120°) = 3/2

*asked on January 12, 2012* -
## Trig

sinAsin2A+sin3Asin6A+sin4Asin13A/sinAcos2A+sin3Acos6A+sin4Acos13A = tan9A

*asked on January 2, 2012* -
## Trigonometry

If A + B + C = 180° prove that Sin2A + sin2B – sin2C = 4cosAcosBsinC

*asked on February 7, 2012* -
## Trig

Prove that 1 + tanAtanA/2 = tanAcotA/2 -1 = secA

*asked on January 3, 2012* -
## Trigonometry

cos2Acos2B + sin²(A-B) - sin²(A+B) = cos(2A+2B)

*asked on January 12, 2012* -
## Trigonometry

If A + B + C = 180°, Prove that Cos²A + Cos²B - Cos²C = 1 – 2sinAsinBcosC

*asked on February 10, 2012* -
## C++

Write a function that takes an int argument and doubles it. The function does not return a value.

*asked on January 2, 2012* -
## Physics

A hemispherical bowl of radius R is rotated about its axis of symmetry which is kept vertical. A small block is kept in the bowl at a position where the radius makes an angle Θ with the vertical. The block rotates with the bowl without any slipping. The

*asked on January 2, 2012* -
## Trigonometry

Prove that sin3A+sin2A-sinA = 4sinAcosA/2cos3A/2

*asked on January 6, 2012* -
## Trigonometry

Prove that sin²A-sin²B/sinAcosA-sinBcosB = tan(A+B)

*asked on January 5, 2012* -
## Trigonometry

Solve the equations for value of x tan mx + cot nx = 0

*asked on December 28, 2011* -
## Maths

How many numbers less than 10000 can be formed by using digits 1,2,3,0,4,5,6,7 ?

*asked on December 22, 2011* -
## Trigonometry

Prove that (tan4A + tan2A)(1-tan²3Atan²A) = 2tan3Asec²A

*asked on January 12, 2012* -
## Trigonometry

Prove that tan2A = (sec2A+1)√sec²A-1

*asked on January 6, 2012* -
## Trigonometry

If A + B + C = 180°, Prove that Sin² (A/2) + sin² (B/2) + sin²(C/2) = 1 – 2sin (A/2) sin (B/2) sin(C/2)

*asked on February 10, 2012* -
## Trigonometry

If A + B + C = 180° prove that cos2A + cos2B – cos2C = -1 -4cosAcosBcosC

*asked on February 7, 2012* -
## Trigonometry

If cospΘ + cosqΘ = o. prove that the different values of Θ form two arithmetical progressions in which the common differences are 2π/p+q and 2π/p-q respectively.

*asked on December 23, 2011* -
## Trigonometry

Prove that sin(n+1)Asin(n-1)A + cos(n+1)Acos(n-1)A = cos2A

*asked on December 30, 2011* -
## Trigonometry

If A + B + C = 180°, Prove that Sin² (A/2) + sin² (B/2) - sin²(C/2) = 1 – 2cos (A/2) cos (B/2) sin(C/2)

*asked on February 10, 2012* -
## Straight Lines

From a given point (h,k) perpendiculars are drawn to the axis whose inclination is w and their feet are joined.Prove that the length of the perpendicular drawn from(h,k) upon this line is hksin²w/√(h² + k² + 2khcosw) and that its equation is hx - ky =

*asked on January 21, 2012* -
## Straight Lines

Find the equation to and the length of the perpendicular drawn from the point(1,1) upon the straight line 3x + 4y + 5 = 0. The angle between the axis being 120°.

*asked on January 21, 2012* -
## Straight Lines

The axes being inclined at an angle of 30°, find the equation to the straight line which passes through the point(-2,3) and is perpendicular to the straight line y + 3x = 6

*asked on January 21, 2012* -
## Straight Lines

From each corner of a parallelogram a perpendicular is drawn upon the diagonal which does not pass through that corner and these are produced to form another parallelogram, show that its diagonals are perpendicular to the sides of the first parallelogram

*asked on January 21, 2012* -
## Straight Lines

If y = xtan(11π/24) and y = xtan(19π/24) represents two straight lines at right angles, prove that the angle between the axis is π/4.

*asked on January 21, 2012* -
## Binomial Theoram

If A be the sum of the odd terms and B the sum of the even terms in the expansion of (x+a)ⁿ. Prove that A² - B² = (x²-a²)ⁿ.

*asked on January 25, 2012* -
## Straight Lines

Find the length of the perpendicular drawn from the point(4,-3) upon the straight line 6x + 3y - 10 = 0. The angle between the axes being 60°.

*asked on January 21, 2012* -
## Straight Lines

With oblique coordinates find the tangent of the angle between the straight lines y = mx + c my + x = d

*asked on January 21, 2012* -
## Trig

IfA=340°, prove that 2cosA/2 = -(v1+sinA) - (v1-sinA)

*asked on January 12, 2012* -
## Trigonometry

Find all the angles between 0° and 90° which satisfy the equation sec²Θcosec²Θ + 2cosec²Θ = 8

*asked on December 28, 2011* -
## Straight Lines

The coordinates of a point P referred to axis meeting at an angle w are (h,k). Prove that the length of the straight line joining the feet of the perpendiculars from P upon the axes is sinw√(h² + k² 2khcosw)

*asked on January 21, 2012* -
## Physics

A turn of radius 20m is banked for the vehicles going at a speed of 36km/h. If the coefficient of static friction between road and the tyre is 0.4, what are the possible speeds of a vehicle so that it neither slips down nor skids up ?

*asked on January 2, 2012* -
## Trigonometry

Solve the equations secΘ - 1 = (√2 - 1)tanΘ

*asked on December 24, 2011* -
## Trigonometry

Prove that cos(-A+B+C) + cos(A-B+C) + cos(A+B-C) + cos(A+B+C) = 4cosAcosBcosC

*asked on January 1, 2012* -
## Binomial Theoram

Show that the coefficient of the middle term of(1+x)power2n is equal to the sum of the coefficients of the two middle terms of (1+x)power2n-1.

*asked on January 25, 2012* -
## Straight Lines

Find the equation to the sides and diagonals of a regular hexagon, two of its sides, which meet in a corner, being the axis of coordinates.

*asked on January 21, 2012* -
## Straight Lines

Prove that the equation to a straight line which passes through the point (h,k) and is perpendicular to the axis of x is x + ycosΘ = h + kcosΘ

*asked on January 21, 2012* -
## Trigonometry

Prove that sec8A-1/sec4A-1 = tan8A/tan2A

*asked on January 5, 2012* -
## Trigonometry

Solve the equation tan²3Θ = cot²a

*asked on December 27, 2011* -
## Trigonometry

Solve the equation cotΘ-abtanΘ = a-b Answer-tanΘ=1/a or -1/b

*asked on December 23, 2011* -
## Trigonometry

Prove that cos(A+B+C)+cos(-A+B+C)+cos(A-B+C)+cos(A+B-C)/sin(A+B+C)+sin(-A+B+C)-sin(A-B+C)+sin(A+B-C) = cotB

*asked on January 1, 2012* -
## Trigonometry

Prove that sin(n+1)A-sin(n-1)A/cos(n+1)A+2cosnA+cos(n-1)A = tanA/2

*asked on January 5, 2012* -
## Trigonometry

Simplify sin{A + (n+1/2)B} + sin{A+(n+1/2)}

*asked on January 1, 2012* -
## Trigonometry

Prove that sin(n+1)Asin(n+2)A + cos(n+1)Acos(n+2)A = cosA

*asked on December 30, 2011* -
## Trigonometry

Solve the equation tan²3Θ = cot²a

*asked on December 27, 2011* -
## Trigonometry

Simplify cos{A + (n-3/2)B} - cos{A+ (n+3/2)B}

*asked on January 1, 2012* -
## Trigonometry

Prove that sin50° - sin70° + sin10° = 0

*asked on January 1, 2012*