Monday, July 13, 2015

How to simplify sqrt(2 + sqrt 3) + sqrt(2 - sqrt 3)?

To calculate this expression, we'll have to use the
identities:


sqrt[a+(sqrtb)] = sqrt{[a+sqrt(a^2 - b)]/2} +
sqrt{[a-sqrt(a^2 - b)]/2}


sqrt[a-(sqrtb)] =
sqrt{[a+sqrt(a^2 - b)]/2} - sqrt{[a-sqrt(a^2 - b)]/2}


Let a
= 2 and b = 3


sqrt[2+(sqrt3)] = sqrt{[2+sqrt(2^2 - 3)]/2} +
sqrt{[2-sqrt(2^2 - 3)]/2}


sqrt[2+(sqrt3)] = sqrt(3/2) +
sqrt(1/2) (1)


sqrt[2-(sqrt3)] = sqrt{[2+sqrt(2^2 - 3)]/2} -
sqrt{[2-sqrt(2^2 - 3)]/2}


sqrt[2+(sqrt3)] = sqrt(3/2) -
sqrt(1/2) (2)


We'll add (1) and (2) and we'll
get:


sqrt[2+(sqrt3)] + sqrt[2-(sqrt3)] = sqrt(3/2) +
sqrt(1/2) + sqrt(3/2) - sqrt(1/2)


We'll eliminate like
terms:


sqrt[2+(sqrt3)] + sqrt[2-(sqrt3)] =
2*sqrt(3/2)


The requested result of the
expression is sqrt[2+(sqrt3)] + sqrt[2-(sqrt3)] =
2*sqrt(3/2).

No comments:

Post a Comment

What is the meaning of the 4th stanza of Eliot's Preludes, especially the lines "I am moved by fancies...Infinitely suffering thing".

A century old this year, T.S. Eliot's Preludes raises the curtain on his great modernist masterpieces, The Love...