Question

If x=√3+1 upon 2 then find the value of

Answer 1

Answer:

x= (√3+1)/2

=> x² = (√3+1)² /4 =( 3 + 1 + 2√3) / 4 = (2+√3)/2

x^3 = (2+√3)/2 * (√3+1)/2 = (2√3+3+2 + √3)/ 4 = (5+3√3)/4

So, 4x^3 + 2x² -8x +7

= 4* (5+3√3)/4 + 2*(2+√3)/2 - 8* (√3+1)/2 +7

= 5 + 3√3 + 2 + √3 - 4√3 - 4 +7

= 4√3- 4√3 +7 + 3

= 10