Top answers

a)By completing the square, prove the quadratic formula starting from ax^2+bx+c=0, b) hence, or otherwise solve 3x^2 + 7x -2= 9, to 3s.f.

a)starting from ax 2 +bx+c=0, divide through by a, x 2 +(b/a)x+c/a=0, complete the square (x+(b/2a)) 2 -(b/2a) 2 +c/a=0, expand (x+(b/2a)) 2 -(b 2 /4a 2 )+c/a=0, Combine fractions and rearrange,(x+(b/2a)) 2 ...
YH
Answered by Yusuf H. • Maths tutor
3901 Views

find the diffrential of 3sin2x+4cos2x

dy/dx=6cos2x-8sin2xExplanation: cos x difrentiates to -sinx, we must times the coefficient of cos2x,(4) , by the differential of 2x (ie 2), giving -(4x2)sin2x.Similarly, sinx differentiates cosx, so using th...
AC
Answered by Amy C. • Maths tutor
6231 Views

A curve has equation y = e^(3x-x^3) . Find the exact values of the coordinates of the stationary points of the curve and determine the nature of these stationary points.

In order to find the stationary points we need to find the first derivative, set it to 0 and solve for x. We can then use this value to find the value for y.y = e (3x-x^3) We know for the derivative of e to ...
PM
Answered by Philip M. • Maths tutor
6243 Views

Solve 7x + 6 > 1 + 2x

To solve a question we want to get the x terms and one sides, the variables, and the numbers on the other side, the constants.7x + 6 > 1 + 2xSubtract 2x from 7x so we only have x terms on the left hand si...
PM
Answered by Philip M. • Maths tutor
3488 Views

Chloe has 3 pieces of wool. One piece is 160mm long, another is 26cm long and the last piece is 0.45m long. What is the total length of wool, in centimetres, that Chloe has?

The question is asking us to give our answer in centimetres, so the first step to solve this problem will be to convert all the lengths into centimetres. 1cm = 10mm so 160mm = 160/10 = 16cm . 1m = 100cm so 0...
FA
Answered by Fizza A. • Maths tutor
4312 Views