Question
If sinx = cotx, then value of (cos^2(x)+2cos^3(x)+cos^4(x)-3)
A) 0 B) -1 C) -2 D)-3
A) 0 B) -1 C) -2 D)-3
Answers
oobleck
sinx = cotx
sinx = cosx/sinx
sin^2x = cosx
1-cos^2x = cosx
cos^2x + cosx - 1 = 0
cosx = (-1±√5)/2
I get -2
Now you can evaluate the expressions
sinx = cosx/sinx
sin^2x = cosx
1-cos^2x = cosx
cos^2x + cosx - 1 = 0
cosx = (-1±√5)/2
I get -2
Now you can evaluate the expressions