Wednesday

April 16, 2014

April 16, 2014

Posted by **Anonymous** on Thursday, April 26, 2012 at 4:55pm.

Please show step-by-step, thank you!

- Trig Question -
**Reiny**, Thursday, April 26, 2012 at 5:56pmconstruct a triangle in quad II with x=-4 and y = 3

since tanØ = y/x or opposite/adjacent

so r^2 = (-4)^2 + 3^2

r = 5

sinx = 3/5 and cosx = -4/5

you have to know that

sin 2x = 2sinxcosx = 2(3/5)(-4/5) = -24/25

cos 2x = cos^2 x - sin^2 x = 16/25 - 9/25 = 7/25

tan 2x = sin 2x/ cos 2x = (-24/25) / (7/25) = -24/7

**Related Questions**

trig - Given that tan 45=1, use tan(x+y) to show that tan 22.5= /2 - 1. (/is ...

trig - the question is: given sec x = 4, tan x < 0, find sin(2x), cos(2x)and ...

Trig. - sec^2xcotx-cotx=tanx (1/cos)^2 times (1/tan)-(1/tan)=tan (1/cos^2) times...

trig - please help me. use trig. identities to find the exact value. tan 25° + ...

trig - please help me. use trig. identities to find the exact value. tan 25° + ...

trig - given that tan(x/2)=a. Express tan(x) and sin(x) in terms of a. Hint: use...

more trig.... how fun!!!! - if you can't help me with my first question hopw you...

Math-Trigonometry - Show that if A, B, and C are the angles of an acute triangle...

trig - h t t p : / / i m g 4 0 . i m a g e s h a c k . u s / c o n t e n t . p h...

Trig - Given that tan(pi/2) = a. Express tan(x) and sin(x) in terms of a. Hint: ...