The power radiated in a horizontal plane by both antennas together is measured by the detector and is found to vary with angle. (a) Is the power detected at $\theta=0$ a maximum or a minimum? Explain. (b) Sketch a graph of $P$ versus $\theta$ to show qualitatively how the power varies with angle $\theta$ (from $-180^{\circ}$ to $+180^{\circ}$ ) if $d=\lambda$. Label your graph with values of $\theta$ at which the power is maximum or minimum. (c) Make a qualitative graph of how the power varies with angle for the case $d=$ $\lambda / 2$. Label your graph with values of $\theta$ at which the power is maximum or minimum.