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Derive double angle formulas from addition formulae

sin2x = 2sinxcosxcos2x = cos²x - sin²x=2 cos²x - 1= 1 - 2sin²xtan2x = (2tanx)/(1-tan²x)

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Find the equation of the normal to the curve x^3 + 2(x^2)y = y^3 + 15 at the point (2, 1)

The first thing when seeing such a question is to find out what the question wants you to do and plan your method to do so.In this case, the question asks you to find the normal of a curv...

Answered by Kelvin L. • Maths tutor

3853 Views

Expand (x-3)(x+7)

FOIL Method: F - First xx = x² O - Outside x7=7x I - Inside -3x=-3x L - Last -37= -21 Add all the results up to get the answer: x²+7x-3x-21 = x²

Answered by Martin L. • Maths tutor

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Find the value of x: 2x^2 - 3x - 4 = 1

2x^2 - 3x - 4 = 1
To solve, we should bring all the terms to one side, and equate the equation to 0. To do this, we should subtract 1 from each side.
2x^2 - 3x - 4 - 1 = 1 - 12x^2 - 3x - 5 = 0

Answered by Prithvie S. • Maths tutor

4107 Views

If Angela gets 50p change from a £2 coin, how much is 250g of butter? (full details below)

Angela wants to bake a cake. She needs:250g flour250g sugar3 eggs125g butterEach costs:1kg flour 90p1kg sugar £1.206 eggs £1.15250g butter xShow your working.(0.25 x 0.9) + (0.25 x 1.2) + (0.5 x 1.15) + 0...

Answered by Natalie M. • Maths tutor

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