Momo's Spech Hw help trend !

[Momo.05]

Hey , there this question that is really bothering me can someone please help me out there!

PROVE:
cot(a+b) = cota.cotb -1/cot(a+b)

Thank you in advance for the help !

[hyperblade01]

Is the meant to be



OR

[Momo.05]

Its the first one

[kamil9876]

[Momo.05]

thank you

[Momo.05]

This heat is getting to me, can someone please solve this question for me;

Solve for x, -pie <(equal to) x <(equal to) pie.

(a) sin(x) = (root2)/(2)
(b) sin(2x) = -(root3)/(2)

[Momo.05]

Sorry in advance that i cant use the latex thing, since my net is capped and its goes funny when i type and stuff =="

[Momo.05]

Nevermind i got it

[Momo.05]

Wait i need some help in the question above but for (b) =="
Thank you for the help :]

[superflya]

ur restricted domain wood now become -2pi<2x<2pi

sinx=-root3/2......x= -pi/3

sin is negative in the 3rd and 4th quadrants so ur other solutions wood be -pi/3 + pi, 2pi + pi/3 ..... Find all values within ur restricted domain

[brightsky]

,

Because is a negative number, we are looking at quadrants 3 and 4.

Draw a unit circle like attached.

The basic angle, that is, the "magnitude" of the angle 2x when drawn on a graph would be

But we are in quadrants 3 and 4 because that is where sine is negative.

By symmetry, we get

But because it is a , we must multiply the domain by 2 as well.

So we need to spin the angle around a whole , and so we get the angles and

Dividing through by 2 we get the angles:

[Momo.05]

Sorry my computer was abit laggy and i couldnt say thank you in time ><
yup, i understand it muchmuchmuch better  now
Thank you !

[Momo.05]

Oh i have another question i dont quite understand..

In this question i was asked to prove that cos(2A) = (1 - tan^2(A))/(1 + tan^2(A))

Which i proved. Then the question asked me to find the exact value of ;

a. tan(pie/12) -> which i used to the tan(A+B) to solve

BUT for part b. the question is

b. tan (pie/8) -> which is 22.5? there isnt any exact values for it.. and i dont know how that related to the cos(2A) thing i proved .. in other words im CONFUSED !!

=.=

[brightsky]

Hmmm...probably a damn question, but is there something you missed whilst reading it? The only exact value I can think of for is just lol. What does the BoB say?

[Momo.05]

Root2 - 1 ?