Maths make you mad!

[babychen_]

My cousin asked me this question some time back. The question was taken form a bridging module for university maths in states. I think it is equivalent to JC maths H2/H3 here in singapore. The thing is, those who claimed to be pro in maths, should try this. hiak hiak...

Question: Find the value of x from the equation

Comments

[czerin]

wtf.

[babychen_]

lol.

[xiaogou]

Gonna use arctan in place of tan^-1 since it's easier to write.

Using the formula arctan(x) + arctan(y) = arctan[(x+y)/(1-xy)],

arctan(6/x) + arctan(1/x)
= arctan[(7/x)/(1-6/x^2)]
= arctan[7x/(x^2-6)]

Taking tan on both sides of the original equation,

7x/(x^2-6) = tan(pi/6) = 1/sqrt(3)

Thus x^2 - 7sqrt(3)x + 6 = 0

and can be solved using quadratic formula which I'm too lazy to do.

QED. :P

[babychen_]

mightymouse21 also got the same answer as u!

fwahhh.. both so smart! =p

hmm.. so when u wan ur kissh? *blush*

[xiaogou]

Haha... means mightymouse was the first to get the answer, not me right?

[babychen_]

he din post here mah. loL

reject my kiss siah.. kaoz ~~~