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(C3) Show that 4csc^2(x) - cot^2(x) = k can be expressed as sec^2(x) = (k-1)/(k-4) where k != 4

The student can answer this in several ways. One using the simple, known identities csc= 1/sin, cot=1/tan, sec=1/cos, tan=sin/cos, sin^2 + cos^2 = 1 and basic algebra is the following: 4csc^2 - cot^2 = k4/si...
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Answered by Fearghus H. • Maths tutor
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The ratio of Adam's age to Bob's age is 1:2. In 12 years time, the ratio of their ages will be 3:5. Calculate their current ages.

Now: In 12 years:A:B A:B1:2x:2x x+12:2x+12 = 3:5 x+12 = 2x+12 3 55(x+12) = 3(2x+12)5x + 60 = 6x + 36x = 24 A:B Adam = 24, Bob = 48x:2x24:2(24)24:48
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Answered by Aaron S. • Maths tutor
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Find the binomial expansion of (-8+4x)^(2/3) up to and including the term in x^2.

The formula booklet is useful for this type of question, but only once we've rearranged the expression into the correct form. The formula booklet expression is: (1 + z)^n = 1 + n z + 0.5 n*(n-1) z^2 + .... T...
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Answered by David M. • Maths tutor
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Simplify: 2x + 6y + 2y - x

Step 1) Rearrange the equation as follows: (2x - x) + (6y + 2y) this makes it easier to see which values you can add together.Step 2) Solve the calculation in each bracket: x + 8y. Successfully simplifying t...
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Answered by Benjamin L. • Maths tutor
4026 Views

Factorise x^2 + 8x + 12 (2017 non-calculator paper)

This question requires you to work through methodically in stages. We want two numbers, a and b, which fit into brackets of the form: (x + a)(x + b). By doing this, we have simplified the expression through ...
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Answered by Ella M. • Maths tutor
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