A 3.00 kHz tone is being produced by a speaker with a diameter of 0.150 m. The air temperature changes from 0 to 29°C. Assuming air to be an ideal gas, find the change in the diffraction angle .

Please tell me where I am going wrong.

first I converted the temp to kelvin
0 = 273k
29°C = 302k

then I converted the kHz to Hz
3.0 kHz = 3000 Hz

I found the wavelenght for the gas at 0

273/3000 = 0.091

then
sin (theta)= 122(0.091/0.150 m)

Sin (theta) = 74.0133

when I put 74.0133(Sin^-1) into the calculator it comes up as error.

Whoa, dudette: Wavelength is not temperature/frequency. YOu need to use temp to get speed of sound, then wavelength is speedsound/freq.