Rationalise the fraction : 5/(3-sqrt(2))

To rationalise a fraction we have to eliminate the surds in the denominator. We know we can multiply the top and the bottom of a fraction by the same thing, as this is equivalent to multiplying by 1. Notice that(3-sqrt(2))(3+sqrt(2))=9-3sqrt(2)+3sqrt(2)-2=9-2=7Then we can multiply the fraction by (3+sqrt(2))/(3+sqrt(2)) to eliminate the surd in the denominator.5/(3-sqrt(2)) = 5/(3-sqrt(2)) x 1 = 5/(3-sqrt(2)) x (3+sqrt(2))/(3+sqrt(2)) = 5(3+sqrt(2))/(3-sqrt(2))(3+sqrt(2)) = 5(3+sqrt(2)/7

MM

Related Maths A Level answers

All answers ▸

(1.) f(x)=x^3+3x^2-2x+15. (a.) find the differential of f(x) (b.) hence find the gradient of f(x) when x=6 (c.) is f(x) increasing or decreasing at this point?


Prove that 2Sec(x)Cot(x) is identical to 2Cosec(x)


y = 4x^3 - 5/x^2 Find dy/dx


Differentiate y(x)=x^2 + 2x + 1, find the turning point and classify it as minimum or maximum.