$(\tan x+1)^2+(\tan x-1)^2=2\sec^2x\\\\\text{use}\ \tan x=\dfrac{\sin x}{\cos x}\\\\L_s=\left(\dfrac{\sin x}{\cos x}+\dfrac{\cos x}{\cos x}\right)^2+\left(\dfrac{\sin x}{\cos x}-\dfrac{\cos x}{\cos x}\right)^2\\\\=\left(\dfrac{\sin x+\cos x}{\cos x}\right)^2+\left(\dfrac{\sin x-\cos x}{\cos x}\right)^2\\\\=\dfrac{(\sin x+\cos x)^2}{\cos^2x}+\dfrac{(\sin x-\cos x)^2}{\cos^2x}\\\\\text{use}\ (a\pm b)^2=a^2\pm2ab+b^2$

$=\dfrac{\sin^2x+2\sin x\cos x+\cos^2}{\cos^2x}+\dfrac{\sin^2x-2\sin x\cos x+\cos^2}{\cos^2x}\\\\=\dfrac{\sin^2x+2\sin x\cos x+\cos^2+\sin^2x-2\sin x\cos x+\cos^2}{\cos^2x}\\\\=\dfrac{2\sin^2x+2\cos^2x}{\cos^2x}=\dfrac{2(\sin^2x+\cos^2x)}{\cos^2x}\\\\\text{use}\ \sin^2x+\cos^2x=1\\\\=\dfrac{2(1)}{\cos^2x}=2\cdot\dfrac{1}{\cos^2x}=2\left(\dfrac{1}{\cos x}\right)^2\\\\\text{use}\ \sec x=\dfrac{1}{\cos x}\\\\=2(\sec^2x)=2\sec^2x=R_s\\\\L_s=R_s\Rightarrow The\ identity$

4 0

3 years ago

Five cards are randomly selected without replacement from a standard deck of 52 playing cards. what is the probability of gettin

EastWind [94]

Ok so it is a standard deck of 52 cards. Theres 4 suites: Hearts, Spades, Clubs and Diamonds.
In each suite there is 13 cards: Ace, King, Queen, Jack, 10, 9, 8, 7, 6, 5, 4, 3, and 2. The probability of you choosing 5 hearts is most likely to be 5/52.

3 0

2 years ago

A car travels 60km in 30 minutes. In how much time will it cover 100 km?

Daniel [21]

Answer:

About 40 Minutes, Or something close to that

Step-by-step explanation:

The car covers 60 km in 90 minutes or its speed = 60 km*60/90 min = 40 km/hr . So to cover 100 km at the same speed it will take 100/40 = 40 Min

5 0

2 years ago

Read 2 more answers

HELP PLEASE 14 POINTS

hram777 [196]

Answer:

To my knowledge of congruency, I would say the answer is A,

Step-by-step explanation:

Hope this helped!!!

8 0

2 years ago