Given:

To find:
The exact value of cos 15°.
Solution:

Using half-angle identity:


Using the trigonometric identity: 

Let us first solve the fraction in the numerator.

Using fraction rule: 

Apply radical rule: ![\sqrt[n]{\frac{a}{b}}=\frac{\sqrt[n]{a}}{\sqrt[n]{b}}](https://tex.z-dn.net/?f=%5Csqrt%5Bn%5D%7B%5Cfrac%7Ba%7D%7Bb%7D%7D%3D%5Cfrac%7B%5Csqrt%5Bn%5D%7Ba%7D%7D%7B%5Csqrt%5Bn%5D%7Bb%7D%7D)

Using
:


let's firstly change the 1.2 to a fraction
![1.\underline{2}\implies \cfrac{12}{1\underline{0}}\implies \cfrac{6}{5} \\\\[-0.35em] ~\dotfill\\\\ (\stackrel{x_1}{10}~,~\stackrel{y_1}{6})\qquad (\stackrel{x_2}{4}~,~\stackrel{y_2}{\frac{6}{5}}) \\\\\\ \stackrel{slope}{m}\implies \cfrac{\stackrel{rise} {\stackrel{y_2}{\frac{6}{5}}-\stackrel{y1}{6}}}{\underset{run} {\underset{x_2}{4}-\underset{x_1}{10}}}\implies \cfrac{~~ \frac{6-30}{5}~~}{-6}\implies \cfrac{~~ \frac{-24}{5}~~}{-6}\implies \cfrac{~~ -\frac{24}{5}~~}{-\frac{6}{1}}](https://tex.z-dn.net/?f=1.%5Cunderline%7B2%7D%5Cimplies%20%5Ccfrac%7B12%7D%7B1%5Cunderline%7B0%7D%7D%5Cimplies%20%5Ccfrac%7B6%7D%7B5%7D%20%5C%5C%5C%5C%5B-0.35em%5D%20~%5Cdotfill%5C%5C%5C%5C%20%28%5Cstackrel%7Bx_1%7D%7B10%7D~%2C~%5Cstackrel%7By_1%7D%7B6%7D%29%5Cqquad%20%28%5Cstackrel%7Bx_2%7D%7B4%7D~%2C~%5Cstackrel%7By_2%7D%7B%5Cfrac%7B6%7D%7B5%7D%7D%29%20%5C%5C%5C%5C%5C%5C%20%5Cstackrel%7Bslope%7D%7Bm%7D%5Cimplies%20%5Ccfrac%7B%5Cstackrel%7Brise%7D%20%7B%5Cstackrel%7By_2%7D%7B%5Cfrac%7B6%7D%7B5%7D%7D-%5Cstackrel%7By1%7D%7B6%7D%7D%7D%7B%5Cunderset%7Brun%7D%20%7B%5Cunderset%7Bx_2%7D%7B4%7D-%5Cunderset%7Bx_1%7D%7B10%7D%7D%7D%5Cimplies%20%5Ccfrac%7B~~%20%5Cfrac%7B6-30%7D%7B5%7D~~%7D%7B-6%7D%5Cimplies%20%5Ccfrac%7B~~%20%5Cfrac%7B-24%7D%7B5%7D~~%7D%7B-6%7D%5Cimplies%20%5Ccfrac%7B~~%20-%5Cfrac%7B24%7D%7B5%7D~~%7D%7B-%5Cfrac%7B6%7D%7B1%7D%7D)
![-\cfrac{\stackrel{4}{~~\begin{matrix} 24 \\[-0.7em]\cline{1-1}\\[-5pt]\end{matrix}~~}}{5}\cdot -\cfrac{1}{\underset{1}{~~\begin{matrix} 6 \\[-0.7em]\cline{1-1}\\[-5pt]\end{matrix}~~}}\implies \boxed{\cfrac{4}{5}}](https://tex.z-dn.net/?f=-%5Ccfrac%7B%5Cstackrel%7B4%7D%7B~~%5Cbegin%7Bmatrix%7D%2024%20%5C%5C%5B-0.7em%5D%5Ccline%7B1-1%7D%5C%5C%5B-5pt%5D%5Cend%7Bmatrix%7D~~%7D%7D%7B5%7D%5Ccdot%20-%5Ccfrac%7B1%7D%7B%5Cunderset%7B1%7D%7B~~%5Cbegin%7Bmatrix%7D%206%20%5C%5C%5B-0.7em%5D%5Ccline%7B1-1%7D%5C%5C%5B-5pt%5D%5Cend%7Bmatrix%7D~~%7D%7D%5Cimplies%20%5Cboxed%7B%5Ccfrac%7B4%7D%7B5%7D%7D)
Answer:
1/12
Step-by-step explanation:
1/2-[-1/4+2/3]
1/2-[-3/12+8/12]
1/2-[5/12]
1/2-5/12
6/12-5/12
1/12
The pick up fee is $2.50.
After each mile, $1.95 is added.
That is, after the first mile, we have;

Isaac total charge = $27.46;
Generally, let the number of miles driven by the taxi be x, then we have;

Solving for the number of miles Isaac travelled, we have;

CORRECT OPTION:
Answer:
V=75 in 3 9 in. 17 in. There are 1 more cubic inches of sand in the pyramid with the greater volume.
Step-by-step explanation: