Find the two real roots of the equation x^4 -5=4x^2 Give the roots in an exact form.

Disguised quadratic. Let y=x^2So quadratic become y^2-4y-5=0so (y-5)(y+1)=0so y=5 and y=-1so x^2 = 5 or -1cannot be -1 as not real henso x^2=5x=+-sqrt(5)

RJ

Related Maths A Level answers

All answers ▸

Why does a 'many to one' function not have an inverse?


Show the sum from n=0 to 200 of x^n given that x is not 1, is (1-x^201)/(1-x) hence find the sum of 1+2(1/2)+3(1/2)^2+...+200(1/2)^199


Express 1/((x^2)(1-3x) in partial fractions.


differentiate y=(5x-2)^5