Welcome to College Confidential!

The leading college-bound community on the web

Sign Up For Free

Join for FREE, and start talking with other members, weighing in on community discussions, and more.

Also, by registering and logging in you'll see fewer ads and pesky welcome messages (like this one!)

As a CC member, you can:

  • Reply to threads, and start your own.
  • Post reviews of your campus visits.
  • Find hundreds of pages of informative articles.
  • Search from over 3 million scholarships.

Math IIC Question

1104199411041994 Registered User Posts: 96 Junior Member
2sinx + cos2x = 2(sinx)^2 - 1

for 0≤x≤2pi

How do I solve this without a graphing calculator?
Post edited by 11041994 on

Replies to: Math IIC Question

  • rspencerspence Registered User Posts: 2,118 Senior Member
    cos 2x = 1 - 2 sin^2 (x), so we have

    2 sin x + (1 - 2 sin^2(x)) = 2 sin^2 (x) - 1

    Let u = sin x, this becomes a quadratic in terms of u. Solve for u. Remember that -1 <= u <= 1, since sin x can only range from -1 to 1, inclusive.
This discussion has been closed.