What is a possible value of sin(theta) when cos2(theta)=0.73? a.0.37b.0.63c.0.26d.0.74

Compare these two waves: the blue and orange waves have the same pitch, but the blue wave is louder. the blue and orange waves have the same volume, but the blue wave has a higher pitch. the orange wave has a higher pitch, but the blue wave is louder. the blue wave has a higher pitch, but the orange wave is louder.

Does anyone know how to solve and graph this: 4 + | a + 2 | < 7the only part i don't get is the "4 +"

Use sigma notation to represent the following series for 9 terms.