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Expand (x-5)(2x-3)

(x-5)(2x-3)= 2x 2 -3x-10x+15 = 2x 2 -13x + 15
SS
Answered by Sharone S. • Maths tutor
5586 Views

You are told that the y is proportional to x^2 and that when y=75, x=5. Find a formula for x in terms of y.

If we know that y is proportional to x 2 then we using the given values we can write 75= 5 2 --> 75=25, however this is obviously not true but all that remains is to multiply the 5 2 by 3 which gives us 7...
JP
Answered by Jenieka P. • Maths tutor
3580 Views

1. (a) Express 7cosx - 24sin x in the form R cos (x + a), (b) hence what is the minimum value of this equation

(a) Rcos (x+a) = Rcosxcosa - Rsinxsina 7cosx - 24sinx = Rcosxcosa - Rsinxsina Rcosa = 7, Rsina = 24 Tan a = 24/7 a = 1.287 (3 S.F.) R 2 = 24 2 + 7 2 R = 25 Therefore 25cos(x + 1.287) (b) minimum value = -1 *...
PB
Answered by Prashan B. • Maths tutor
15037 Views

Find the normal to the curve y = x^2 at x = 5.

Differentiate the original equation (y = x^2) to find the gradient (m) of the line which is a tangent to the curve. Dy/dx = 2x Therefore m = 2 Calculate the negative reciprocal (m2) which will give the gradi...
AS
Answered by Aphisha S. • Maths tutor
4363 Views

Use the identity for sin(A+B) to find the exact value of sin 75.

From reading the question, we need to use the addition formula for sin(A+B)= sinAcosB+cosAsinB. So we need to think what are two common values for sine and cosine that we know and have exact answers for that...
RD
Answered by Ruth D. • Maths tutor
4961 Views