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How do i factorise 20 + 10x?

Firstly, we can take a look at the degree x's in each term. It seems like they share a common degree of 0. In other words, we will not be able to factor out the x's in the expression.Secondly, we need to fin...
TS
Answered by Tarun S. • Maths tutor
13840 Views

The region R is bounded by the curve y=sqrt(x)+5/sqrt(x) the x-axis and the lines x = 3, x = 4. Find the volume generated when R is rotated through four right-angles about the x-axis. Give your answer correct to the nearest integer.

The general formula for a volume of rotation is pi times the integral of y^2. The first step is to square y. this can be done by squaring the first term, squaring the last term and finding twice the product....
MH
Answered by Matthew H. • Maths tutor
7228 Views

Rationalise the denominator of the following fraction: 1/(√2 + 1)

We start with 1/(√2 + 1) Normally with rationalising surd denominators we multiply the top and bottom of the fraction by the denominator. But this time we have a surd ADDED by a rational number. In this case...
RM
Answered by Richard M. • Maths tutor
34169 Views

The Curve C has the equation 2x^2-11+13. The point Q lies on C such that the gradient of the normal to C at Q is -1/9. Find the x-co-ordinate of Q

The first ste here is the find the general equation for the gradient tangential to the curve. This is done by differentiation of the equation to give 4x-11=dy/dx. dy/dx is the gradient. Now we are given the ...
MH
Answered by Matthew H. • Maths tutor
5466 Views

The radius of a circular disc is increasing at a constant rate of 0.003cm/s. Find the rate at which the area is increasing when the radius is 20cm.

The rate at which the area is increasing, dA/dt, can be written with terms we know or can find out easily: dA/dt=dA/dr x dr/dt.Area of a disc, A = (pi)r^2dA/dr=2(pi)rRate of change of radius, dr/dt=0.003cm/s...
HH
Answered by Henry H. • Maths tutor
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