A second harmonic is generated in an elastic cord of length l stretched between two clamps. The vertical displacement (y) of a cord element as a function of the horizontal position x and time t is given by the equation ${"mathml":"<math style=\"font-family:stix;font-size:16px;\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mstyle mathsize=\"16px\"><mi>y</mi><mfenced><mrow><mi>x</mi><mo>,</mo><mi>t</mi></mrow></mfenced><mo>=</mo><mn>2</mn><mi>A</mi><mi>sin</mi><mo> </mo><mfenced><mrow><mfrac><mrow><mn>2</mn><mi mathvariant=\"normal\">π</mi></mrow><mi>λ</mi></mfrac><mi>x</mi></mrow></mfenced><mi>sin</mi><mfenced><mrow><mi>ω</mi><mi>t</mi></mrow></mfenced></mstyle></math>","truncated":false}$ . Make a sketch of the standing-wave pattern.

A nylon guitar string vibrates according to the equation y = 0.2 sin(2.28 x)sin(40π t) where x and y are in cm and t in seconds. What is the amplitude A of the two transversal waves that form this standing wave pattern?