Use a compound angle formula to develop an equivalent expression for cos3x and use that expression to solve the equation 2cos3x+cos2x+1=0on the interval 0x2.. Express your answer(s) as exact radians and approximate radians rounded to two decimals where applicable. Show your work. **HINT** express everything in terms of cosx.

The average human heart beats 1.15 \cdot 10^51.15⋅10 5 1, point, 15, dot, 10, start superscript, 5, end superscript times per day. there are 3.65 \cdot 10^23.65⋅10 2 3, point, 65, dot, 10, start superscript, 2, end superscript days in one year.how many times does the heart beat in one year? write your answer in scientific notation, and round to one decimal place.

Determine the difference: 3.2 × 1010 – 1.1 × 1010. write your answer in scientific notation.

What percent of 18 is 24? and plz explain thx.