Top answers

what does it mean if "b^2 - 4ac < 0" for a quadratic equation (eg y = a*x^2 + b*x + c)

The question comes from the quadratic equation r = (-b +- sqrt(b 2 - 4ac)/2a where r is the root or x coordinate where the line crosses the x-axsis (the y coordinate is always 0). If b 2 - 4ac &lt; 0 then to...
NW
Answered by Nick W. • Maths tutor
5933 Views

Determine whether the line with equation 2x+ 3y + 4 = 0 is parallel to the line through the points with coordinates (9, 4) and (3, 8).

Parallel means that the lines have the same gradient/slope . For example, the lines in an equal sign are parallel.Consider the standard equation of a line is: y = mx + c where m is the gradient . Rewriting o...
DE
Answered by Dominique E. • Maths tutor
7124 Views

The circle C has centre (2,1) and radius 10. The point A(10,7) lies on the circle. Find the equation of the tangent to C at A and give it in the form 0 =ay + bx + c.

Whenever possible it is always a good idea to draw a graph to give a better understanding of what is going on in the question. As we have already been given a point on the tangent, namely A(10,7), it is a go...
GG
Answered by George G. • Maths tutor
5535 Views

Find partial fractions of : (x+7) / ((x-3)(x+1)^2)

First, separate the algebraic fraction:(x+7) / ((x-3)(x+1) 2 = A/(x+3) + B/(x+1) + C/(x+1) 2 Multiply both sides by (x-3)(x+1) 2 : (x+7) = A(x+1) 2 + B(x+1)(x+3) + C(x+3) Set x=-1 in order to eliminate A and...
JV
Answered by Janni V. • Maths tutor
3630 Views

How do you know when to integrate by parts?

This is usually a good idea if you have an integral with two functions multiplied together when one of the functions differentiates to a constant (could take more than one differentiation).For example to fin...
DH
Answered by Dominic H. • Maths tutor
3461 Views