D *14.24 Derive T(s) for the op amp–RC circuit in Fig. P14.24. Show that |T(jω)| = 1 and find ϕ(ω). We wish to use this circuit as a variable phase shifter by adjusting R. If the input signal frequency is 5 × 103 rad/s and if C = 10 nF, find the values of R required to obtain phase shifts of –30°, –60°, –90°, –120°, and –150°. Note that this circuit is known as all-pass filter.