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These are the selling prices of 5 houses in 2007: £145 000, £170 000, £215 000, £90 000, £180 000 (a) Work out the mean selling price.

The mean is also known as the average. To work out the mean you need to add all the house prices together and then divide by the number of houses. So in this example the total price of the houses is 145000+1...
JP
Answered by James P. • Maths tutor
3432 Views

The random variable J has a Poisson distribution with mean 4. Find P(J>2)

P(J>2) = P(J=0)+P(J=1) [split it up] P(X=t)= (V^t)/t!*e^V where V=4 in this case [use the formula] P(J>2) = 4^0/0!*e^4 + 4^1/1!*e^4 =1/e^4 + 4/e^4 = 5e^-4 which is roughly 0.0916
NC
Answered by Nathan C. • Maths tutor
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Given 2x^2-3y^2=2, find the two values of dy/dx when x=5.

First solve for the exact point on the line by substituting 5 into the original equation. You should get y=+-4. Now implicitly differentiate the equation: 4x-6y(dy/dx)=0. Rearranging this will yield the foll...
KU
Answered by Kalid U. • Maths tutor
7753 Views

The quadratic equation x^2 - 2kx + (k - 1) = 0 has roots α and β such that α^2 + β^2 = 4. Without solving the equation, find the possible values of the real number k.

We know in a quadratic x^2 +bx + c = 0, -b/a = α + β and c/a = αβ. Therefore, α + β = -(-2k) = 2k, and αβ = k - 1. (Both are divided by the coefficient in front of x which is 1 so can be ignored. Now (α + β)...
RT
Answered by Ralph T. • Maths tutor
17798 Views

3. The point P lies on the curve with equation y=ln(x/3) The x-coordinate of P is 3. Find an equation of the normal to the curve at the point P in the form y = ax + b, where a and b are constants.

P- (3,0) y=ln(x/3) u=x/3 y=ln(u) ​​​​​​ du = 1/3 dy = 1/u = 3 dx du dy = du x dy dx dx du = 1/3 x 3 = 1 gradient at normal = -1 equation at normal = y = m(x) + c 0 = -3 + c 3 = c Answer: equation at normal =...
KB
Answered by Kaushalya B. • Maths tutor
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