# Kiirsty

Popular questions and responses by Kiirsty-
## Math binomial formula and sequence

a) use the binomial formula to find the 5th term of the expansion (2x - 3)^8 ------ i got 90720x? b) Find a_n, the general term for a geometric sequence, given that the fourth term, a_4 is 16 and the seventh term is -128 c) Find the sum of

*asked on May 25, 2014* -
## Math - Ratio

a) on a map the scale used is 1: 10,000. if two towns are separated by a straight 2.5 km road, what will be the distance between them on the map? b) on a map 2.5 km is represented as 0.5 cm. what scale is being used on the map? thanks heaps!

*asked on May 25, 2014* -
## geometry math help

"the inside of a carton is measured and is found to be width of 40cm, length 60cm and depth 30 cm. it is to be packed 2 layers deep with cylindrical tins that have a radius of 5cm and height of 15cm (outside measurements)." a) show that 48 tins can be

*asked on May 26, 2014* -
## Math functions help

given f(x) = 1-2x, and g(x) = x^2+1, find: a) g(-2) ---- i get 5 ? b) f(x+1) c) g`f(x) --- there is like a degree symbol circle between g and f.. d) f^-1(x)

*asked on May 25, 2014* -
## more logarithms help!

the depreciated value, V, of a car can be calculated using V = C91-r)^n, where C is the original value, r is the rate of depreciation per yeat and n is the age of the car in years. how long would it take for a $24,000 car to be reduced to a value of $2500

*asked on May 25, 2014* -
## quadratics math

the height of a triangle is 4cm shorter than its base. if the triangle has an area of 48cm2, find the length of the base of the triangle.

*asked on May 25, 2014* -
## logarithm math help

express: In(√x / y^2z ) thanks :)

*asked on May 25, 2014* -
## math quadratic equations

a) expand and simplify: (4x-3)(x+1) i get 4x^2+x-3 ? b) factorise: 2x^2 + 13x + 15 c) find y-int, x-int and vertex of: y= x^2-3x-4 i get y-int = -4, but loose it from there :(

*asked on May 25, 2014* -
## math trig

a 3.8m ladder rests against a vertical wall and makes an angle of 38 degrees with the wall. how far does the ladder reach up the wall?

*asked on May 25, 2014* -
## Math - Logarithms

can someone pleaaase help me with these "solve for x": a) log_x 100 = 5 b) 3^x+5 = 81 c) log (4x + 2) - log 2 = log 6x thanks heaps!

*asked on May 25, 2014* -
## Math - Linear Equations

"the period of a pendulum, T (in seconds) varies directly with the square root of the length of the pendulum, L (in centimeters)". Given that a pendulum of length 9cm has a period of 0.63 seconds, find: a) The period of a pendulum of length 25cm b) The

*asked on May 24, 2014* -
## Math - Linear Equations

"A trucking firm has 8 trucks, some carry a load of 10 tonnes and others carry a load of 5 tonnes. When all 8 trucks are carrying a full load, the total load is 70 tonnes." Develop and solve simultaneous equations to determine the number of trucks of each

*asked on May 23, 2014* -
## Math - Variation

under certain conditions, the thrust T of a propeller varies jointly as the fourth power of it's diameter, d, and the square of the number, n, of revolutions per second. What happens to the thrust if n is doubled and d is halved?

*asked on May 23, 2014* -
## Math - Trigonometry

From an aeroplane, at an altitude of 2.3km, the angle of depression of the airport is 32Degrees and the angle of depression of the town is 18degrees (both are in direct line ahead of the plane) How far is the town from the airport?

*asked on May 13, 2014* -
## Math - Proportion

The acoustic intensity, I, of a sound wave is proportional to the square of the pressure amplitude, P, and inversely proportional to the velocity, v, of the wave. a) what is the proportionality relationship? b) what happens to the intensity if both the

*asked on May 13, 2014* -
## Math - Trigonometry

A 2m long ladder leaning against a wall makes an angle of 38 degrees with the wall. how far is the base of the ladder from the wall?

*asked on May 13, 2014*