Top answers

What is the gradient of the curve 3x^3 + 7x at the point x=3?

The gradient or the slope of a curve is defined as the change in the y direction over the change in the x direction (dy/dx). In order to calculate a formula for the gradient of a curve we must differentiate ...
JK
Answered by Junaid K. • Maths tutor
3690 Views

Find the values of k for which the equation (2k-3)x^2- kx+(k-1)=0 has equal roots.

For a quadratic to have equal roots, the value of the discriminant (b 2 -4ac) =0. This means that the quadratic formula yields only one result (or two equal roots), since x=(-b ±0)/2a , thus if a and b are c...
HK
Answered by Henry K. • Maths tutor
12690 Views

How do I rationalise the denominator? (Surds)

If you have a fraction where the denominator is a surd, such as 5/(1+sqrt(2)), you need to multiply the denominator by another number so that it becomes a a whole number. If you multiply either the denominat...
LC
Answered by Leanne C. • Maths tutor
3775 Views

Use the structure of sodium chloride to explain why it has a high melting point. (2 marks)

There are strong electrostatic forces of attraction between oppositely charged ions within sodium chlorides giant lattice. The strong electrostatic forces must be broken in order to melt sodium chloride. Sig...
EC
Answered by Evie C. • Chemistry tutor
10024 Views

factorise: 3x^2+13x-30

(3x-5)(x+6)factors of 90 (3x30): 1x90, 6x15, 9x10, 5x18and add up to 13 can only be 5 and 1818-5=13 5/3 or 18/3=6 and 5x6=30so must be (3x-5)(x+6) and check by expanding with FOIL method
MS
Answered by Mary S. • Maths tutor
3989 Views