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write (x+2)(x+3)(x+5) in the form ax^3+bx^2+cx+d

First take (x+2)(x+3) and expand to get x 2 +3x+2x+6, which can be simplified to equal x 2 +5x+6.Then mutiple x 2 +5x+6 by (x+5). This will give you x 3 +5x 2 +5x 2 +25x+6x+30. Simplify this to equal x 3 +10...
CH
Answered by Cora H. • Maths tutor
3907 Views

Using the identity cos(A+B)= cosAcosB-sinAsinB, prove that cos2A=1-2sin^2A.

Use cos(A+B)=cosAcosB-sinAsinB and let A=B so cos(A+A)=cosAcosA-sinAsinA this means cos(2A)=cos 2 A-sin 2 A and since cos 2 A+sin 2 A=1, cos 2 A=1-sin 2 A. Therefore, by subbing cos 2 A=1-sin 2 A into cos(2A...
RF
Answered by Rebecca F. • Maths tutor
22687 Views

A curve has the equation: x^3 - x - y^3 - 20 = 0. Find dy/dx in terms of x and y.

x 3 - x - y 3 - 20 = 0 Find dy/dx. Differentiate with respect to x. 3x 2 - 1 - 3y 2 (dy/dx) = 0Therefore: dy/dx = (3x 2 - 1)/3y 2
KP
Answered by Karishma P. • Maths tutor
3861 Views

Alex designs a game for people to play, using two fair five-sided spinners. A person wins the game when both spinners land on the same letter. People pay 40p for each game they play. The prize for a win in £1. Is she likely to raise money?

In order to raise money, we need the average number of wins to be smaller than the average number of losses by at least a factor of 0.4. The average number of wins will be the number of games multiplied by t...
ML
Answered by Megan L. • Maths tutor
3558 Views

Sam works for £14 per hour. When Sam works more than 8 hours a day, he is paid overtime for each hour he works more than 8 hours at 1½ times his normal rate of pay. Sam worked for 12 hours. Work out the total amount of money Sam earned.

Find the wage received from normal rate= 8x14=112. We then find the wage received from working overtime by finding the number of extra hours worked (12-8=4) multiplied by the overtime wage of (1½ x14= 1.25x1...
JC
Answered by Joseph C. • Maths tutor
6145 Views