Physics question help please

Hi, please could I have some help on question 7c of this paper: https://bestexamhelp.com/exam/cambridge-international-a-level/physics-9702/2024/9702_s24_qp_41.pdf
I don’t understand why the power time graph is identical for both?
Thanks!

The graph in Fig. 7.2 is |V_maxsin(ωt)|, while the graph in Fig. 7.3 will be ~|V_maxsin(ωt)|².
The alternating power supply across the resistor will be a sinusoidal voltage, and the power dissipated will be ~V_max²sin²(ωt).
The graph of V_max²sin²(ωt) is the same as of |V_maxsin(ωt)|², and you can verify it by using any graphing software.