Top answers

Jack has 20 sweets. Will also has 20 sweets. Jack gives Will x sweets. Jack then eats 5 of his sweets. Will then eats half of his sweets. Write expressions for the number of sweets Jack and Will now have.

They both start with 20 sweets. To get the total number of sweets that Jack has, you need to take away x because that is the amount that he gives to will. Jack then eats 5 of his sweets so you need to take a...
LM
Answered by Lucy M. • Maths tutor
5695 Views

Supposing y = arcsin(x), find dy/dx

Suppose: y = arcsin(x) Then, x = sin(y) And, dx/dy = cos(y) ----- (1) Using: dy/dx = 1/(dx/dy); Thus 1 becomes: dy/dx = 1/cos(y) ------ (2) Using: sin^2(y) + cos^2(y) = 1; We can rearrange 2 to: dy/dx = 1/sq...
JN
Answered by James N. • Maths tutor
7438 Views

There are 420 balls in a ball pool. There is a combination of violet, blue, yellow and green balls. 2/7 are violet, 35% are blue and the ratio of yellow to green is 4:5. How many of each colour ball is there in the ball pool?

Together, the total number of balls is 420. 2/7 of the total 420 balls are violet. Therefore the number of violet balls can be calculated by the equation 2/7 x 420/1 = 840/7=120. There are 120 violet balls i...
LW
Answered by Lauren W. • Maths tutor
4437 Views

Find the coordinates of the turning points of the curve y = 4/3 x^3 + 3x^2-4x+1

First differentiating by the rule that x n differentiates to nx n-1 we have that dy/dx = 4x 2 +6x-4. At the turning points of a curve the differential is equal to 0 so we set 0=dy/dx = 4x 2 +6x-4, by factori...
TE
Answered by Theo E. • Maths tutor
9551 Views

Solve the linear simultaneous equations: 3x + 5y = 45, 2x - 9y = -7

x = 10, y = 3. From the second equation, we have x = (9y - 7)/2. Substituting this expression for x into the first equation gives 3(9y - 7)/2 + 5y = 45. 3(9y - 7) + 10y = 90. 27y - 21 + 10y = 90. 37y = 111. ...
CW
Answered by Cameron W. • Maths tutor
4126 Views