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How do I know when to use the cosine or sine rule?

Both the cosine and sine rule are used to find either a missing side length or angle of a triangle that doesn't have a right angle. The cosine rule is used when you know the length of two sides and the an...

Answered by Molly B. Maths tutor
7160 Views

Derive double angle formulas from addition formulae

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

Answered by Alexander H. Maths tutor
3239 Views

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
3298 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
6883 Views

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

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