How do you solve for cos2x = 2 cosx sinx?

Maria · Sep 26, 2004

I have on stupid question left:
Why do I get 4 angles instead og just 2?
Is it because tan =1?

arildno · Sep 27, 2004

You get 4 distinct angles because you must solve tan(2x)=1 rather than tan(x)=1
If for example, you were to solve tan(4x)=1, you would have even more distinct solutions
(You could work out how many for yourself)

Maria · Sep 28, 2004

thanks a lot for answering all my stupid questions...

How do you solve for cos2x = 2 cosx sinx?

High School Ant on a stretchy rope puzzle

Undergrad Is infinity a necessary concept?

High School Potato paradox

Undergrad Descartes’ Geometry of Square Roots

Undergrad Three Circle Problem

Mathematica NDSolve with forcing function via "digital waveguide"

MATLAB Unable to produce desired results using state-space model with observer for inverted pendulum

Insights Revisiting the Velocity-Time Function

Insights Remote Operated Gate Control System

Insights AI Enriched Problem Solving

Insights Thinking Outside The Box Versus Knowing What’s In The Box

Insights Why Entangled Photon-Polarization Qubits Violate Bell’s Inequality

Insights Quantum Entanglement is a Kinematic Fact, not a Dynamical Effect

How do you solve for cos2x = 2 cosx sinx?

Similar threads

Solve Simple Trig Problem: cosx - cosx*sinx = 1/3

Solving Identity Question: (cosx)^2 = (1 + cos2x)/2

Solve Derivative of y=e^cosx*sinx

Undergrad Def. of derivative and cosx=sin(Pi/2-x) to prove y'=-sinx

Undergrad Solving 2nd Order DEs w/ Undermined Coefficients & e^x, cosx, sinx

Undergrad Lim x→7π/4 of (cosx + sinx)/(cos2x)

Trigonometric Integrals: Solving ∫ cosx+sin2x/sinx

Struggling with Integrating 1/(cosx - sinx)^2?

Undergrad How to Integrate cosx/((sinx)^2 + 1) with Respect to x

Undergrad Is the Equation (1-x)Cosx = Sinx Continuous and Solvable in (0,1)?