Science

Math

Humanities

... and beyond

Socratic Meta
Featured Answers

Topics

How do you solve #cosx (2sinx + 1) = 0#?

1 Answer

Jul 21, 2015

Solve: cos x(2sin x + 1) = 0

Explanation:

cos x(2sin x + 1) = 0
a. cos x = 0 --> #x = pi/2 and x = 3pi/2#

b. #sin x = - 1/2#. Trig table gives:
#x = - pi/6# or #(11pi)/6#.
Trig unit circle gives another arc #x = (7pi)/6# that has same sine value.

Finally, within interval #(0, 2pi)#, there are 4 answers:
#pi/2#; #(7pi)/6#, #(3pi)/2#; and #(11pi)/6.#

Related questions

See all questions in Solving Trigonometric Equations

Impact of this question

16235 views around the world

You can reuse this answer
Creative Commons License