Nathan's Blog

In section 8-5, you use identities to get to the same trig function; if you can't try to make it tan or cot by sin/cos or cos/sin.

THINGS THAT B-ROB AND THE BOOK SAID WE CAN'T DO:
1.) Divide by a trig function when solving to cancel.
2.) Cancel from the inside of a trig function; Ex. sin (2x)/2: YOU CANNOT CANCEL THE 2's

Here's an example:

sin^2 x-sinx=cos^2 x In Radians
sin^2-sinx=1-sin^2 x
2sin^2 x-sinx-1=0
(2sin^2 x-2sinx)+(sinx-1)=0
2sinx(sinx-1)+(sinx-1)
(2sinx+1) (sinx-1)
2sinx+1=0 sinx-1=0
x=sin^-1(-1/2) x=sin^-1(1)
x=30(plugged in as positive) x=90

Sin is negative is Q III and IV
So, x=210 degrees, and 330 degrees
210 x π/180=7π/6
330 x π/180=11π/6
90=π/2

So, finally, your answers are 7π/6, 11π/6, and π/2.

I understood section 8-5 pretty well, but the graphs in the sections before still confuse me a little. So, overall, chapter 8 was not that bad. It's late on Sunday and more than half the class has not done the blog. WOW