How Do I Solve the Equation 117.72 = 100sin2x + 28cosx for x?

  • Thread starter Thread starter Todd0012
  • Start date Start date
  • Tags Tags
    Stuck
AI Thread Summary
To solve the equation 117.72 = 100sin2x + 28cosx, one approach is to graph the right-hand side for various x values and find intersection points with the line y = 117.72. Another method involves using trigonometric identities to transform the equation, such as substituting sin2x with 2cos²x - 1, leading to a quadratic equation in terms of cosx. Evaluating specific x values can also help determine if they satisfy the equation. Overall, combining graphical and algebraic methods can effectively identify solutions for x.
Todd0012
Messages
6
Reaction score
0
Stuck please help -- 117.72=100sin2x + 28cosx

Im trying to find an angle and I am stuck

117.72=100sin2x + 28cosx

What do i do now?
 
Physics news on Phys.org
You can always assume a value of x and evaluate the RHS of the equation to see if it equals the LHS.

You can graph the RHS of the equation for different values of x, and then draw a line y= 117.72 and use the intersection points to estimate the values of x which are the solutions.

You can use trig identities on the RHS to see if you obtain an equivalent expression in x which may be more amenable to solution.

Take yer pick.
 
use the identity (2cos(x)^2 -1) = sin2x to make it a quadratic equation with cosx instead of x
 
(2cos(x)^2 -1) = sin2x

Thats a trig Identity?
 
ah my memory was bad that one is for cos2x sorry
 

Thread 'Struggling to understand the concept of this question (ice cube in water optics question)'

TL;DR Summary: I came across this question from a Sri Lankan A-level textbook. Question - An ice cube with a length of 10 cm is immersed in water at 0 °C. An observer observes the ice cube from the water, and it seems to be 7.75 cm long. If the refractive index of water is 4/3, find the height of the ice cube immersed in the water. I could not understand how the apparent height of the ice cube in the water depends on the height of the ice cube immersed in the water. Does anyone have an...
View full post »

Thread 'Rolling without slipping on a curved surface'

Kindly see the attached pdf. My attempt to solve it, is in it. I'm wondering if my solution is right. My idea is this: At any point of time, the ball may be assumed to be at an incline which is at an angle of θ(kindly see both the pics in the pdf file). The value of θ will continuously change and so will the value of friction. I'm not able to figure out, why my solution is wrong, if it is wrong .
View full post »

Similar threads

Resistance of the ground problem
Replies
4
Views
3K
Spring System in Harmonic Motion. How do I find
Replies
3
Views
2K
Find the normal force and magnitude of acceleration.
Replies
4
Views
14K
Calculating Flywheel Inertia Using Conservation of Energy Equations?
Replies
14
Views
2K
Torque before slipping in a refrigerator
Replies
3
Views
1K
Solving a Ball Thrown off a Cliff: How Long Does it Take?
Replies
4
Views
2K
Projectile Motion (not on Earth)
Replies
11
Views
1K
Motion - How do you find the time in the air of an object
Replies
20
Views
2K
Dimensional Analysis for Multi-Layer Flow Equations
Replies
24
Views
2K
Stuck on Question A? Get Help Here!
Replies
3
Views
2K

Hot Threads

Recent Insights

Back
Top