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

(x-5)(2x-3)= 2x²-3x-10x+15

= 2x² -13x + 15

Answered by Sharone S. • Maths tutor

4724 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 x²then we using the given values we can write 75= 5²--> 75=25, however this is obviously not true but all that remains is to multiply the 5<...

Answered by Jenieka P. • Maths tutor

2919 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.)

R²

Answered by Prashan B. • Maths tutor

13273 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) ...

Answered by Aphisha S. • Maths tutor

3634 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 t...

Answered by Ruth D. • Maths tutor

3855 Views