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solve 2cos^2(x) - cos(x) = 0 on the interval 0<=x < 180

we start y factoring and solving for each equation: cos(x) (2cos(x) - 1) = 0 this means: cos(x) = 0 and cos(x) = 1/2 from the first equation we get: x = 90 and from the second equation using the known trigon...
DS
Answered by Dimitris S. • Maths tutor
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Expand the brackets and simplify: 7(2x+3y)-x(14-y)

= 14x+21y-14x+xy =y(21+x)
IA
Answered by Ilan A. • Maths tutor
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simplify and rationalise 1/ sqrt(12)

Start by simplifying the denominator - We can write sqrt(12) as sqrt (4*3). - This can be written as sqrt(4) * sqrt(3) - We know the square root of 4 is 2. sqrt(3) is not a integer so we leave that as sqrt(3...
MF
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Express 2cos(x) + 5sin(x) in the form Rsin(x + a) where 0<a<90

Expanding Rsin(x + a): Rsin(x + a) = Rsin(x)cos(a) + Rcos(x)sin(a) Comparing coefficients of sin(x), cos(x) with first expression leads to: Rsin(a) = 2, Rcos(a) = 5 Dividing these equations gives: tan(a) = 2...
DH
Answered by Dan H. • Maths tutor
12540 Views

A girl kicks a ball at a horizontal speed of 15ms^1 off of a ledge 20m above the ground. What is the horizontal displacement of the ball when it hits the ground?

As we are looking for the horizontal displacement first we look at horizontal motion. We know that the horizontal velocity is 15ms^-1 but we dont know the time so we can't work out the horizontal displacemen...
VW
Answered by Victoria W. • Maths tutor
4543 Views